water and climate change: understanding the risks and ... · water and climate change:...
TRANSCRIPT
November 2009
Water and Climate Change:
Understanding the risks and making Climate-smart investment deCisions
Vahid AlavianHalla Maher QaddumiEric DicksonSylvia Michele DiezAlexander V. DanilenkoRafik Fatehali HirjiGabrielle PuzCarolina PizarroMichael JacobsenBrian Blankespoor
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
Pub
lic D
iscl
osur
e A
utho
rized
November 2009
Water and Climate Change:
Understanding the risks and making Climate-smart investment deCisions
iii
Table of ConTenTs
Foreword........................................................................................................................ ix
Acknowledgements...................................................................................................... xi
AbbreviAtions.And.Acronyms..................................................................................... xiii
executive.summAry........................................................................................................ xvintroduction................................................................................................................ xvthe.context................................................................................................................. xvclimate.change,.hydrologic.cycle,.and.water................................................................xviiwater.sector.is.highly.exposed.to.climate.change.with.implication..beyond.the.sector........................................................................................................xixworld.bank.water.investments.and.climate.change........................................................ xxProjections.of.key.hydrologic.indicators.for.water.planning............................................xxiiexposure.of.the.bank.investment.to.climate.change...................................................... xxviclimate-smart.investments.must.explicitly.consider.risk................................................ xxviiway.forward............................................................................................................. xxix
cHAPter.1:.context.And.overview............................................................................... 1introduction................................................................................................................. 1climate.change.and.the.world.bank............................................................................. 2climate.change.and.the.water.sector............................................................................. 3value.added.and.content.of.this.report.......................................................................... 5
cHAPter.2:.imPAct.oF.climAte.cHAnge.on.tHe.Hydrologic.cycle.And.tHe..wAter.resource.bAse...................................................................................................... 9
the.climate.system.and.the.hydrologic.cycle.are.intimately.linked..................................... 9evidence.is.mounting.that.climate.change.is.occurring.and.that.it.is.altering..the.hydrologic.cycle.................................................................................................... 10Future.changes.in.climate.are.projected.to.lead.to.a.further.acceleration..and.intensification.of.the.hydrologic.cycle.................................................................... 11Hydrologic.change.and.increased.variability.will.have.a.significant.impact..on.the.water.resource.base......................................................................................... 14
uncertainties.in.projected.climate.change.impacts................................................ 14runoff.and.river.discharge................................................................................... 14groundwater...................................................................................................... 15water.quality...................................................................................................... 17Floods.and.droughts........................................................................................... 18Freshwater.ecosystems........................................................................................ 19
cHAPter.3:.imPAct.oF.climAte.cHAnge.on.wAter.AvAilAbility.And.use................. 21climate.change.is.expected.to.increase.global.water.stress.and.insecurity....................... 21
surface.water.stress.assessments.......................................................................... 21groundwater.stress.assessments.......................................................................... 22water.security..................................................................................................... 22transboundary.basins......................................................................................... 23
water.dependent.sectors.and.climate-induced.hydrologic.changes................................. 24
iv
Health............................................................................................................... 24Agriculture......................................................................................................... 26industry.and.transport.sector................................................................................ 27energy/Hydropower............................................................................................ 27natural.ecosystems............................................................................................. 28
impact.of.non-climatic.drivers.on.water.availability.and.use.patterns.............................. 29
cHAPter.4:.tHe.cost.oF.vulnerAbility.to.Hydrologic.cHAnge.And..increAsed.vAriAbility..................................................................................................... 31
the.developing.world.is.particularly.vulnerable.to.climate.change.................................. 31vulnerability.to.surface.water.stress...................................................................... 32vulnerability.to.groundwater.stress....................................................................... 32
costs.to.the.most.vulnerable....................................................................................... 34implications.for.sustainable.development.and.the.bank’s.mission.for..poverty.reduction........................................................................................................ 35
cHAPter.5:.climAte.And.Hydrology.Projections.For.investment.decisions.... 37introduction............................................................................................................... 37key.issues.in.climate.change.impact.assessments.......................................................... 37
resolution.and.scale.in.impact.assessments.......................................................... 37generating.and.capturing.climate.change.projections........................................... 40
Analytical.framework.................................................................................................. 41key.hydrologic.variables.for.water.planning.and.management............................... 41sres.scenarios.and.gcms.................................................................................. 42timeframe.of.analysis......................................................................................... 42Application.of.tools.to.dialogues.at.national,.river.basin.and..Project.level.Analysis.......................................................................................... 43
Hydrologic.drivers.and.data........................................................................................ 44Historical.climate................................................................................................ 44Historical.observed.runoff.................................................................................... 44Historical.indicators.as.baseline.for.future.water.investment.assessment.................. 44
Projections.using.climate.moisture.index...................................................................... 47runoff.projections....................................................................................................... 49basin.yield.projections................................................................................................ 49extreme.events.projections.......................................................................................... 52base.flow.projections.................................................................................................. 57net.irrigation.demand.projections................................................................................ 59
cHAPter.6:.climAte.cHAnge.And.tHe.world.bAnk.wAter.PortFolio.................... 63introduction............................................................................................................... 63Framework.for.analysis............................................................................................... 63content.of.the.water.portfolio...................................................................................... 64climate.change.content.of.the.portfolio....................................................................... 67
Adaptation.to.climate.change.in.the.portfolio....................................................... 67types.of.Adaptation.interventions.as.identified.in.the.Portfolio................................ 69
cHAPter.7:.exPosure.oF.tHe.wAter.PortFolio.to.current.Hydrologic..vAriAbility.And.Future.climAte.cHAnge..................................................................... 75
introduction............................................................................................................... 75
v
exposure.criteria.and.investment.exposure.................................................................... 75exposure.to.current.hydrologic.variability.and.future.climate.change.............................. 76
irrigation.and.drainage....................................................................................... 76urban.water.supply.and.sanitation....................................................................... 77rural.water.supply.and.sanitation......................................................................... 77Flood.control.................................................................................................... 78river.basin.management.and.multi-purpose.infrastructure..................................... 78
Potential.exposure.of.the.investment.portfolio................................................................ 84
cHAPter.8:.risk-bAsed.decision.mAking.For.‘climAte.smArt’.investments........... 87introduction............................................................................................................... 87sector.investment.decisions.must.be.made.under.increased.risk.and..uncertainty................................................................................................................. 88A.framework.for.risk-based.decision.making.for.water.investments................................. 90
definitions.and.terminology................................................................................. 90risk-based.decision.framework............................................................................ 93stage.1.–.identify.problem,.objectives,.performance.criteria.and.rules..for.decision-making............................................................................................ 93stage.2.–.Assess.risks......................................................................................... 94stage.3.–.identify.and.evaluate.options.to.manage.risk......................................... 95
considerations.for.the.water.sector.............................................................................. 96susceptibility.of.water.systems.to.climate.change................................................... 96Adaptation.options.for.water.systems................................................................. 96categories.of.adaptation.options......................................................................... 98class.of.projects.for.which.risk-based.analysis.would.be.particularly.essential........ 100
Assessing.risk:.application.to.multi-purpose.infrastructure.projects................................ 101Hydrologic.drivers.for.multi-purpose.hydraulic.infrastructure................................. 101Project.components.......................................................................................... 101mapping.the.climate.change.impact.onto.project.components............................. 103scoring.of.component.risk................................................................................. 103Assessment.of.project.components.most.at.risk................................................... 105
cHAPter.9:.next.stePs:.An.AgendA.on.climAte.cHAnge..For.tHe.wAter.PrActice............................................................................................. 107
continue.to.strengthen.the.analytical.foundation........................................................ 107incorporate.hydrologic.variability.and.climate.resiliency.considerations..in.bank.operations................................................................................................... 108strengthen.bank.expertise.on.water.and.climate.change.............................................. 109
cHAPter.10:.reFerences.............................................................................................. 111
AnnexesAnnex.A:.summAry.oF.wAter.PortFolio.by.region............................................... 115
Africa.region........................................................................................................... 115east.Asia.and.Pacific.region...................................................................................... 116europe.and.central.Asia.region................................................................................ 117latin.America.and.caribbean.region......................................................................... 119middle.east.and.north.Africa.region......................................................................... 120south.Asia.region.................................................................................................... 121
vi
Annex.b:.risk-bAsed.decision.mAking.FrAmeworks............................................... 123united.kingdom.climate.impacts.Programme............................................................. 123Australian.greenhouse.office................................................................................... 125
Annex.c:.AdAPtAtion.oPtions.For.multi-PurPose.inFrAstructure..................... 129
Annex.d:.glossAry.oF.terms..................................................................................... 133
Figuresdistribution.of.world.bank.water.projects.for.Fy06–08.(active).and.Fy09–10.(pipeline)............xxiwater.investments.by.volume.and.category.(services/resource.management)..........................xxiiclimate.moisture.index:.range.of.cgms.for.three.emission.scenarios.for.various.regions...... xxiiiProjected.percent.change.in.hydrologic.indicators.for.2030.from.1961–1990.baseline.......... xxivProjected.exposure.map.by.hydrologic.drivers.(2030)............................................................ xxvPotential.exposure.of.water.projects.to.climate.change.in.2030.and.2050............................ xxviPotential.exposure.of.water.investments.to.climate.change.in.2030.and.2050...................... xxviiFigure.2.1:. the.Hydrologic.cycle...................................................................................... 10Figure.2.2:. large-scale.relative.changes.in.annual.runoff.(water.availability,.in.percent)..
for.the.period.2090–2099,.relative.to.1980–1999............................................ 16Figure.2.3:. global.estimates.of.climate.change.impact.on.groundwater.recharge................. 17Figure.3.1:. reported.countries.with.groundwater.depletion.................................................. 23Figure.4.1:. some.preliminary.results.for.applying.the.climate.vulnerability.index.(cvi)..
for.comparison.of.vulnerability.by.region.at.present.and.in.30.years................... 32Figure.4.2:. illustrative.map.of.future.climate.change.impacts.related.to.freshwater..
which.threaten.the.sustainable.development.of.the.affected.regions.................... 36Figure.5.1:. the.cone.of.uncertainty.in.scale.and.resolution.of.modeling............................... 39Figure.5.2:. section.of.the.sAr.region.showing.0.5˚.by.0.5˚.grid.scale,.2.5˚.by.2.5˚..
(gcm).grid.scale.(dark.larger.grids),.and.catchment.boundaries.in.color............ 40Figure.5.3:. range.of.relative.change.from.historical.climate.for.different.gcms...
mean.is.shown.in.heavy.line............................................................................ 41Figure.5.4:. multi-model.averages.and.assessed.ranges.for.surface.warming......................... 42Figure.5.5:. modeled.historical.baseline.indicators.at.catchment.scale.for.bank.regions..
(1961–1990)..units.are.in.mm/yr..................................................................... 45Figure.5.6:. modeled.historical.baseline.indicators.at.catchment.scale.for.Africa..
(1961–1990)..lines.on.the.map.delineate.catchment.boundaries..units.are..in.mm/yr........................................................................................................ 46
Figure.5.7:. climate.moisture.index.range.for.each.climate.scenario.and..each.bank.region............................................................................................ 48
Figure.5.8:. climate.moisture.index.range.comparison.of.bank.and.non-bank.regions........... 49Figure.5.9:. Projected.percent.change.in.runoff.for.2030..................................................... 50Figure.5.10:.Projected.percent.change.in.runoff.for.2030.at.catchment.level.–.Africa.region..
catchment.boundaries.are.not.delineated......................................................... 51Figure.5.11:.impact.of.climate.change.on.reservoir.yield.and.Adaptations........................... 52Figure.5.12:.Projected.percent.change.in.basin.yield.for.2030.............................................. 53Figure.5.13:.Projected.percent.change.in.basin.yield.for.2030.at.catchment..level.–..
Africa.region..catchment.boundaries.are.not.delineated................................... 53Figure.5.14:.Projected.percent.change.in.low.flows.(drought).for.2030.................................. 55Figure.5.15:.Projected.percent.change.in.high.flows.(floods).for.2030................................... 56
vii
Figure.5.16:.Projected.percent.change.in.low.flows.(drought).for.2030.at.catchment.level.–..Africa.region..catchment.boundaries.are.not.delineated................................... 56
Figure.5.17:.Projected.percent.change.in.high.flows.(floods).for.2030.at.catchment.level.–..Africa.region..catchment.boundaries.are.not.delineated................................... 57
Figure.5.18:.Projected.percent.change.in.base.flow.for.2030................................................ 58Figure.5.19:.Projected.percent.change.in.base.flow.for.2030.at.catchment.level.–..
Africa.region..catchment.boundaries.are.not.delineated................................... 59Figure.5.20:.Projected.percent.change.in.water.deficit.index.for.2030.................................... 61Figure.5.21:.Projected.percent.change.in.water.deficit.index.for.2030.at.catchment.level.–..
Africa.region..catchment.boundaries.are.not.delineated................................... 61Figure.6.1:. classification.of.water.systems........................................................................ 64Figure.6.2:. location.of.world.bank.water.projects.for.Fy06–08.(active).and..
Fy09–10.(pipeline).......................................................................................... 65Figure.6.3:. world.bank.water.lending.volume.(shading).and.class.(bar).for.Fy06–08............ 65Figure.6.4:. water.lending.as.a.share.of.overall.regional.lending.in.the.Fy06–08.................. 66Figure.6.5:. world.bank’s.water.lending.and.number.of.projects.for.Fy06–08..
and.Fy09–10................................................................................................. 66Figure.6.6:. regional.distribution.of.the.world.bank.water.lending.for.the.Fy06–08............... 67Figure.6.7:. lending.distribution.in.water.services.and.water.resources.for.the.Fy06–08......... 67Figure.6.8:. Projects.with.potential.adaptation.measures.(%)................................................. 68Figure.6.9:. types.of.climate.change.interventions............................................................... 70Figure.6.10:.type.of.intervention.for.projects.in.Fy06–08.and.Fy09–10................................. 73Figure.7.1:. Projected.2030.exposure.map.to.change.in.water.deficit.index........................... 79Figure.7.2:. Projected.2030.and.2050.exposure.maps.to.change.in.water.deficit.index.–..
Africa.region.................................................................................................. 79Figure.7.3:. Projected.2030.exposure.map.to.change.in.low.flows.(drought)......................... 80Figure.7.4:. Projected.2030.and.2050.exposure.maps.to.change.in.low.flows.(drought).–..
Africa.region.................................................................................................. 80Figure.7.5:. Projected.2030.exposure.map.to.change.in.base.flow....................................... 81Figure.7.6:. Projected.2030.and.2050.exposure.maps.to.change.in.base.flow.–..
Africa.region.................................................................................................. 81Figure.7.7:. Projected.2030.exposure.map.to.change.in.high.flows.(floods)........................... 82Figure.7.8:. Projected.2030.and.2050.exposure.maps.to.change.in.high.flows.(floods).–..
Africa.region.................................................................................................. 82Figure.7.9:. Projected.2030.exposure.map.to.change.in.basin.yield...................................... 83Figure.7.10:.Projected.2030.and.2050.exposure.maps.to.change.in.basin.yield.–..
Africa.region.................................................................................................. 83Figure.7.11:.exposure.of.water.projects.to.climate.change.in.2030.and.2050........................ 84Figure.7.12:.exposure.of.water.investments.to.climate.change.in.2030.and.2050.................. 85Figure.8.1:. consequence.and.probability.components.of.risk.............................................. 91Figure.8.2:. stages.in.risk-based.decision.making................................................................ 93Figure.8.3:. stage.1.–.objectives.identification.and.system.characterization.......................... 94Figure.8.4:. stage.2.–.Assessment.of.risks........................................................................... 95Figure.8.5:. stage.3.–.options.identification.and.assessment.to.reduce.risk........................... 95Figure.A1:. Africa.region.water.investment.for.the.Fy06–08.period.................................... 115Figure.A2:. east.Asia.and.Pacific.region.water.investment.for.the.Fy06–08.period............... 116Figure.A3:. europe.and.central.Asia.region.water.investment.for.the.Fy06–08.period......... 118Figure.A4:. latin.America.and.caribbean.region.water.investment.for.the..
Fy06–08.period............................................................................................ 119
viii
Figure.A5:. middle.east.and.north.Africa.region.water.investment.for.the..Fy06–08.period............................................................................................ 120
Figure.A6:. south.Asia.region.water.investment.for.the.Fy06–08.period............................. 122Figure.b1:. the.ukciP.framework................................................................................... 124Figure.b2:. the.Australian.framework.............................................................................. 125
tAblestable.2.1:. changes.in.key.Hydrologic.variable................................................................. 13table.3.1:. mediating.processes.and.potential.effects.on.health.of.changes..
in.temperature.and.weather.............................................................................. 25table.4.1:. Preliminary.assessment.of.vulnerability.of.groundwater.in.world.bank..
regions.to.climate.change................................................................................ 33table.5.1:. spatial.resolution.of.Ar4.iPcc.Archived.gcms................................................ 38table.5.2:. coverage.area.of.1-degree.latitude.by.1-degree.longitude................................ 38table.5.3:. Available.Ar4.models,.scenarios,.and.variables.via.iPcc.................................. 43table.5.4:. gcm.and.associated.base.cmis.used.for.each.scenario.and.regions..
eAP,.ecA,.and.lcr.......................................................................................... 47table.5.5:. gcm.and.associated.base.cmis.used.for.each.scenario.and.regions.mnA,..
sAr,.and.AFr................................................................................................. 47table.5.6:. summary.changes.in.runoff.projections.for.bank.regions.................................... 50table.5.7:. summary.changes.in.basin.yield.projections.for.bank.regions............................. 52table.5.8:. summary.changes.in.low.flow.projections.for.bank.regions................................ 54table.5.9:. summary.changes.in.high.flow.projections.for.bank.regions............................... 55table.5.10:. summary.changes.in.base.flow.projections.for.bank.regions.............................. 58table.5.11:. summary.changes.in.water.deficit.index.projections.for.bank.regions.................. 60table.7.1:. list.of.water.systems.and.indicators................................................................. 75table.7.2:. irrigation.and.drainage.exposure.level.descriptions............................................ 77table.7.3:. urban.water.supply.and.sanitation.exposure.level.description............................. 77table.7.4:. rural.water.supply.and.sanitation.exposure.level.description............................... 77table.7.5:. Flood.control.exposure.level.description............................................................ 78table.7.6:. river.basin.management.exposure.level.description........................................... 78table.8.1:. matrix.of.hydrologic.drivers.and.infrastructure.components............................... 104table.8.2:. scoring.by.category.for.each.component........................................................ 104table.8.3:. scoring.matrix.template................................................................................. 105
boxesbox.2.1:. weather,.climate,.and.climate.variability............................................................. 9box.2.2:. mass.loss.of.glaciers....................................................................................... 12box.2.3:. Primary.sources.of.uncertainty.in.projections.of.hydro-climatic.change................ 14box.3.1:. malaria.in.Africa.under.climate.change............................................................ 25box.3.2:. Hydropower.in.Zambezi.basin.under.climate.change......................................... 28box.3.3:. Fate.of.ecosystems.in.southern.Africa.under.climate.change............................... 29box.3.4:. non-climatic.drivers.of.change.in.freshwater.systems......................................... 30box.8.1:. risk.and.uncertainty........................................................................................ 91box.8.2:. standardized.indicators.to.assess.the.vulnerability.of.regions.and..
systems.to.climate.change................................................................................ 97box.8.3:. Potential.impact.some.of.key.hydrologic.drivers............................................... 102
ix
foreword
the.iPcc’s.Fourth.Assessment.report.(2007).and.other.technical.studies.have.concluded.that.observational.records.and.climate.projections.provide.abundant.evidence.that.freshwater.resources.are.vulnerable.and.have.the.potential.to.be.strongly.impacted.by.climate.change,.with.wide.ranging.consequences.on.human.societies.and.ecosystems..each.bank.region.is.likely.to.face.a.unique.set.of.water-related.climate.change.challenges,.deriving.from.such.impacts.as.accelerated.glacier.melt;.altered.precipitation,.runoff.and.recharge.patterns.and.rates;.extreme.floods.and.droughts;.water.quality.changes;.saltwater.intrusion.in.coastal.aquifers;.and.changes.in.water.uses..in.this.context,.the.2010.world.development.report.emphasizes.that.water.will.have.to.be.used.more.efficiently,.that.climate-smart.practices.will.have.to.be.adopted.and.that.countries.will.need.to.co-operate.to.manage.shared.water.resources.
Potential.adaptation.strategies.to.the.impacts.of.climate.change.on.water.resources.have.become.central.to.the.dialogue.on.water.policy.reforms.and.investment.programs.with.client.countries..in.order.to.complement.regional.efforts.already.underway,.and.to.support.future.regional.initiatives,.the.water.Anchor.in.the.energy,.transport.and.water.department.(etw).in.the.sustainable.development.vice.Presidency.has.undertaken.a.two-year.analytical.work.on.climate.change.and.water.
the.main.objective.is.to.provide.analytical,.intellectual.and.strategic.assistance.to.the.regions.for.incorporating.adaptation.to.climate.variability.and.change.in.their.work.programs..the.report.focuses.on.water.and.water-related.issues.and.investments..A.particular.focus.of.the.work.is.on.reducing.the.vulnerability.of.water.sector.investments.to.the.impacts.of.climate.change..Furthermore,.the.report.provides.a.first.version.of.a.tool.that.can.be.used.to.assess.exposure.and.screen.the.investment.portfolio.on.a.regional.basis.
this.etw.Anchor.Flagship.consists.of.this.main.report.and.a.series.of.supporting.technical.reports.and.papers.reflecting.the.output.of.a.two.year.effort..the.series.includes.a.synthesis.of.the.state-of-the-art.of.the.science.as.related.to.climate.and.hydrologic.cycle;.an.analysis.of.climate.change.impacts.on.groundwater.resources.and.adaptation.options;.a.review.of.the.bank’s.current.water.investment.portfolio.with.regards.to.the.extent.to.which.climate.change.is.considered.at.the.project.design.level;.and.an.evaluation.of.the.exposure.of.the.world.bank.water.sector.investments..Also.included.in.this.Flagship.product.is.a.menu.of.adaptation.options.for.increased.robustness.and.resiliency.of.water.systems.to.climate.variability/change,.and.a.framework.for.risk-based.analysis.for.water.investment.planning..it.is.hoped.that.this.work.will.help.enhance.knowledge.and.understanding.of.both.bank.staff.and.client.country.professionals.for.making.better-informed.decisions.regarding.water.investments..
Jamal Saghir director,.energy,.transport.and.water.chair,.water.sector.board
xi
aCknowledgemenTs
this.report.provides.an.overview.of.the.series.of.reports.and.documents.prepared.as.part.of.the.Flagship.product.of.the.water.Anchor.of.the.energy,.transport,.and.water.department..the.effort.was.led.by.vahid.Alavian.under.the.overall.guidance.of.Abel.mejia.and.jamal.saghir..the.core.water.and.climate.change.team.responsible.for.this.work.includes.Halla.maher.Qaddumi,.eric.dickson,.sylvia.michele.diez,.Alexander.v..danilenko,.rafik.Fatehali.Hirji,.gabrielle.Puz,.carolina.Pizarro,.michael.jacobsen,.all.from.the.water.Anchor.and.brian.blankespoor.from.dec.research.group.
significant.contributions.were.made—through.preparation.of.technical.reports,.background.notes,.thematic.inputs,.and.model.simulation—by.Professor.kenneth.strzepek.and.his.climate.change.team.at.the.university.of.colorado.and.massachusetts.institute.of.technology.(mit);.by.stratus.consulting,.particularly.joel.smith.and.his.team;.by.nick.Pansic.and.his.team.at.montgomery.watson.Harza.(mwH);.and.by.sinclair.knight.merz.(skm),.particularly.rick.evans.and.his.team..these.consultants.effectively.served.as.partners.and.members.of.the.water.and.climate.change.team.at.the.water.Anchor.during.the.course.of.this.work.
the.water.Anchor.team.is.grateful.to.the.peer.reviewers.and.other.bank.staff.who.provided.valuable.insight.and.guidance.from.the.concept.note.stage.through.to.the.completion.of.this.Flagship.product..they.are.doug.olson,.ronald.Hoffer,.Ashok.subramanian.and.the.Africa.water.group,.dean.cira,.ian.noble,.kseniya.lvovsky.and.the.env.climate.change.team,.nagaraja.rao.Harshadeep,.john.briscoe,.winston.yu,.walter.vergara,.guy.Alaerts,.Aziz.bouzaher,.raffaello.cervigni,.julia.bucknall,.marianne.Fay,.and.Ariel.dinar..external.experts,.including.eugene.stakhiv,.us.Army.corps.of.engineers.water.resource.institute.and.stephen.Foster,.gw-mAte/dFid.provided.valuable.input.and.guidance.to.this.work.
editing.of.this.report.was.completed.on.june.1,.2009.
Disclaimer
this.volume.is.a.product.of.the.staff.of.the.international.bank.for.reconstruction.and.development/the.world.bank..the.findings,.interpretations,.and.conclusions.expressed.in.this.paper.do.not.necessarily.reflect.the.views.of.the.executive.directors.of.the.world.bank.or.the.governments.they.represent..the.world.bank.does.not.guarantee.the.accuracy.of.the.data.included.in.this.work..the.boundaries,.colors,.denominations,.and.other.information.shown.on.any.map.in.this.work.do.not.imply.any.judgment.on.the.part.of.the.world.bank.concerning.the.legal.status.of.any.territory.or.the.endorsement.or.acceptance.of.such.boundaries.
the.material.in.this.publication.is.copyrighted..copying.and/or.transmitting.portions.or.all.of.this.work.without.permission.may.be.a.violation.of.applicable.law..the.international.bank.for.reconstruction.and.development/.the.world.bank.encourages.dissemination.of.its.work.and.will.normally.grant.permission.to.reproduce.portions.of.the.work.promptly.
For.permission.to.photocopy.or.reprint.any.part.of.this.work,.please.send.a.request.with.complete.information.to.the.copyright.clearance.center,.inc.,.222.rosewood.drive,.danvers,.mA.01923,.usA,.telephone.978-750-8400,.fax.978-750-4470,.http://www.copyright.com/..All.other.queries.on.rights.and.licenses,.including.subsidiary.rights,.should.be.addressed.to.the.office.of.the.Publisher,.the.world.bank,.1818.H.street.nw,.washington,.dc.20433,.usA,.fax.202-522-2422,[email protected].....
xii
xiii
abbreviaTions and aCronyms
AAA. Advisory.and.analytic.activitiesAcrA. country.Adaptation.to.climate.risk.AssessmentAFr. Africa.regionAogcm. Atmospheric-ocean.general.circulation.modelcAs. country.Assistance.strategycc. climate.changecdm. clean.development.mechanismceiF. clean.energy.for.development.investment.FrameworkcF. carbon.FinancecoP. conference.of.the.Partiesco2. carbon.dioxidecPiA. country.Policy.and.institutional.Assessmentdec. development.economics.departmentdPl. development.policy.lendingeAP. east.Asia.and.the.PacificecA. europe.and.central.Asiaenso. el.niño-southern.oscillationesmAP. energy.sector.management.Assistance.Program4Ar. Fourth.Assessment.report.(iPcc)FAr. First.Assessment.report.(iPcc)gcm. general.circulation.modelgdP. gross.domestic.productgeF. global.environment.FacilitygHg. greenhouse.gasesgPg. global.public.goodibrd. international.bank.for.reconstruction.and.developmentidA. international.development.AssociationiFc. international.Finance.corporationiPcc. intergovernmental.Panel.on.climate.changekm. kilometerlcr. latin.America.and.the.caribbeanmdg. millennium.development.goalsmigA. multilateral.investment.guarantee.AgencymnA. middle.east.and.north.Africamoses. met.office.surface.exchange.schemenAo. north.Atlantic.oscillationnAPA. national.Adaptation.Programme.of.ActionodA. official.development.assistancePcmdi. Program.for.climate.model.diagnostics.and.intercomparisonPPiAF. Public-Private.infrastructure.Advisory.Facilityppm. parts.per.millionPPP. Public-Private.PartnershipPrsP. Poverty.reduction.strategy.PaperPsdi. Palmer.drought.severity.indexrcm. regional.climate.modelsAr. second.Assessment.report.(iPcc)sAr. south.Asia.reigon
xiv
sccF. special.climate.change.Fundsd. statistical.downscalingseA. strategic.environmental.Assessmentskm. sinclair.knight.merzsres. special.report.on.emissions.scenariosssA. sub-saharan.AfricaswAp. sectorwide.approachtA. technical.assistancetAr. third.Assessment.report.(iPcc)undP. united.nations.development.ProgrammeuneP. united.nations.environment.ProgrammeunFccc. united.nations.Framework.convention.on.climate.changewbg. world.bank.groupwdr. world.development.reportwwF. world.wildlife.Fund
xv
exeCuTive summary
introduction
Climate change is real, and taking prudent measures to plan for and adapt to climate change must become an integral part of the Bank’s water practice..there.is.now.ample.evidence.that.increased.hydrologic.variability.and.change.in.climate.has.and.will.continue.have.a.profound.impact.on.the.water.sector.through.the.hydrologic.cycle,.water.availability,.water.demand,.and.water.allocation.at.the.global,.regional,.basin,.and.local.levels..many.economies.are.at.risk.of.significant.episodic.shocks.and.worsened.chronic.water.scarcity.and.security..this.can.have.direct.and.severe.ramifications.on.the.economy,.poverty,.public.health.and.ecosystem.viability..this.report.documents.the.results.of.the.first.two.years.of.a.sustained.effort.at.the.energy,.transport,.and.water.department.of.the.world.bank.to.understand.the.risks.of.climate.change.to.the.water.sector.and.to.identify.ways.to.manage.these.risks.for.better.and.climate-smart.investment.decisions.
This report and the analytical work leading to it are focused on key topics related to the impact of climate change on the water cycle and water investments. specifically,.the.topics.addressed.are:.a.better.understanding.of.the.science.and.uncertainties.of.climate.change.projections.as.related.to.the.hydrologic.cycle;.translating.the.climate.projections.to.projection.of.hydrologic.indicators.useful.in.policy.and.planning.of.water.investments;.a.review.of.the.world.bank.water.portfolio.for.climate.change.content.and.adaptation.options.considered;.and.finally.an.examination.of.the.exposure.of.the.portfolio.to.climate-induced.changes.in.hydrologic.drivers.if.the.active.portfolio.were.placed.in.2030.and.2050..special.care.has.been.taken.to.provide.the.reader.with.an.understanding.of.the.critical.assumptions.behind.the.climate.change.projections,.hydrologic.models,.and.application.of.the.science.in.practice..cautionary.notes.are.also.provided.where.common.misunderstandings,.misconceptions,.or.pitfalls.may.occur.in.making.use.of.the.climate.change.information.in.making.investment.decisions..the.results.reported.herein.focus.on.the.impact.of.climate.change.on.the.water.cycle.as.the.primary.driver.of.the.water.sector.and.are.meant.for.use.at.the.policy.and.planning.level.in.making.investment.decisions..the.findings.here.are.not.intended.for.detailed.project.design.applications..with.the.best.available.knowledge.on.climate.change.and.water.as.the.foundation,.economics.of.adaptation,.social,.poverty,.and.environmental.aspects.can.now.be.addressed.and.are.on.the.agenda.for.the.follow.up.work.
The context
Climate change is a development issue for the Bank and its clients with significant implications in the water sector. wbg.clients,.by.virtue.of.their.geographic.location.and.often.low.coping.capacity,.are.among.the.most.affected..the.bank’s.2007.report.IDA and Climate Change: Making Climate Action Work for Development provides.compelling.evidence.that.the.distribution.of.major.climate-related.risks.around.the.world.is.skewed.against.poor.countries..the.bank’s.2009.development.and.climate.change.strategic.Framework.(dccsF).(world.bank,.2008a).asserts.that.climate.change.is.a.development.issue,.among.others,.and.recognizes.the.water.sector.as.one.that.will.be.heavily.impacted.by.climate.change..the.2010.world.development.report.focuses,.among.other.factors,.on.the.land.and.water.interface.for.managing.competing.demands.and.creating.new.opportunities.for.climate-smart.development..many.client.countries.in.partnership.with.the.world.bank.group.have.begun.to.take.action.to.adapt.their.water.sector.to.implications.of.climate.change.and.resulting.hydrologic.impacts..this.process.is.supported.by.analytical.and.advisory.assistance.on.water.and.climate.change.carried.out.by.regional.units,.as.well.as.the.water.Anchor..incorporating.climate.change.in.the.portfolio.
xvi
has.been.steadily.increasing.in.response.to.client.demands..A.number.of.stand-alone.climate.change.projects.have.also.been.financed.through.various.grant.and.lending.instruments.and.they.are.increasing..the.recent.financial.crisis,.as.well.as.the.food.and.fuel.price.crises.put.stress.on.many.economies.and.sectors,.including.water..However,.this.provides.a.unique.opportunity.to.use.the.bank’s.increased.engagement.to.close.the.financial.gap.for.thinking.and.investing.smartly.by.taking.into.account.the.wider.climate.change.issues.
Each World Bank region, even each country and each river basin face a unique set of climate change-related water challenges..depending.on.the.hydrologic.regime,.regional.and.sub-regional.hydrology.and.climate.variability.have.a.direct,.but.differential,.impact.on.the.various.water.use.areas..Floods/droughts,.water.availability/allocation.and.water.quality.management.are.affected.by.climate.change.and.have.an.upward.linkage.to.the.economy..indirect.and.second.order.impacts.can.also.be.significant.in.water.storage.lakes.and.reservoirs;.agricultural.production;.navigation;.and.the.increased.vulnerability.of.ecosystems..many.client.countries.are.particularly.vulnerable.to.the.impacts.of.hydrologic.variability.and.climate.change.given.weak.institutions.and.institutional.capacity,.high.levels.of.poverty,.insufficient.stock.of.water.management.and.services.infrastructure.and.dependence.of.the.rural.economy.on.agriculture..the.gap.between.availability.of.water.storage.infrastructure.in.developed.and.developing.countries.is.wide..climate.change.may.increase.or.reduce.the.need.for.water.storage.infrastructure.depending.on.its.impact.on.the.hydrologic.cycle..one.key.question.concerns.the.strategies.that.need.to.be.put.in.place.to.mitigate.the.negative.impacts.of.climate.change..Potential.adaptation.strategies.to.the.impacts.of.climate.change.on.water.resources.have.become.central.to.the.dialogue.on.water.policy.reforms.and.investment.programs.with.client.countries.
Conventional interventions are necessary but not sufficient..water.practitioners.have.long.coped.with.and.designed.for.variability.in.hydrology..consequently,.numerous.examples.of.adaptation.to.hydrological.variability.and.extreme.events.exist.in.the.water.sector..implementing.the.“good.practices”.more.widely.(e.g.,.efficient.irrigation.technologies,.water.harvesting,.increased.sub-surface.storage,.etc.).would.go.a.long.way.in.confronting.the.climate.change.challenge..Adapting.to.climate.change.must.continue.to.build.on.conventional.interventions.while.addressing.the.immediate.challenges,.but.must.make.a.major.shift.in.thinking,.planning.and.designing.water.investments.of.the.future..new.approaches.in.technology.and.management,.as.well.as.the.development.of.flexible.and.“smart”.systems.that.can.be.operated.to.anticipate.and.react.to.changing.circumstances.must.be.developed,.particularly.in.light.of.uncertainties.in.projected.impacts..new.design.standards.and.criteria.will.also.need.to.be.developed.for.a.changed.hydrology.characterized.by.increased.variability.and.uncertainty..guidelines.for.mainstreaming.adaptation.into.project.design.must.take.all.of.these.aspects.into.account.if.they.are.to.be.effective.
This report contributes to the World Bank agenda on climate change and more specifically, informs the water sector investments on climate issues and climate-smart adaptation options. using.the.existing.knowledge.and.additional.analysis.commissioned.by.the.world.bank.water.Anchor,.the.report.illustrates.that.climate.change.is.affecting.the.hydrologic.cycle.and.the.projected.future.hydrology.will.have.a.direct.impact.on.the.water.resources.base—availability,.usage,.and.management..depending.on.the.type.of.the.water.investment,.this.impact.can.be.positive,.negative,.or.neutral..the.report.addresses.the.stress.on.and.vulnerability.of.the.water.systems.through.use.of.reliability,.resilience,.and.robustness.as.the.key.indicators.of.sensitivity.of.water.systems.for.climate.induced.failure..current.practices.in.the.sector.are.examined.in.order.to.better.understand.the.state-of-the-science.for.incorporating.current.and.future.variability.and.
xvii
change.in.hydrology.and.climate.in.the.bank’s.portfolio.for.project.planning.and.design..new.and.innovative.practices.taking.into.account.adaptation.options.for.water.systems.and.risk-based.decision.making.in.water.investments.are.reviewed.and.assessed.for.application.to.investments.in.infrastructure..the.climate.change.dimension.is.placed.within.the.context.of.the.impact.of.other.factors.(within.and.outside.the.sector).such.as.population.growth.(and.associated.increase.in.demand).and.land.management.(particularly.as.related.to.water),.which.in.some.cases.may.be.far.more.significant.and.critical.than.that.of.climate.change.in.some.parts.of.the.world..Finally,.recommendations.for.a.progressive.agenda.on.water.and.climate.change.are.made.
Climate change, hydrologic cycle, and water
Hydrologic cycle as the key external driver of the water cycle is accelerating due to climate change..Projected.increases.in.global.temperatures.are.associated.with.changes.in.the.hydrologic.cycle,.including.increased.atmospheric.water.vapor,.changes.in.precipitation.patterns.(frequency.and.intensity),.as.well.as.changes.in.groundwater.and.soil.moisture..these.changes.
Key Variables Observed Trends Projections for 21st Century
Precipitation trend.is.unclear..general.increases.in.
precipitation.over.land.from.30on.to.85on..
notable.decreases.from.10os.to.30on.
increase.(about.2%/oc).in.total.
precipitation..High.latitude.areas.generally.
projected.to.increase..many.low.to.mid-
latitude.areas.projected.to.decrease..
changes.at.the.regional.scale.vary.
Atmospheric
water vapor
content
increasing.in.lower.atmosphere.(lower.
troposphere;.about.1%/decade).in.specific.
humidity;.little.change.in.relative.humidity
increasing
Intensity of
precipitation
disproportionate.increase.in.volume.of.
precipitation.in.heavy.or.extreme.precipitation.
events
increasing.(about.7%/oc)
Droughts drought,.as.measured.by.the.Palmer.drought.
severity.index,.increased.in.the.20th.century,.
although.some.areas.became.wetter
increasing.in.many.areas,.particularly.
lower.latitudes..decreasing.in.many.high.
latitude.areas..Patterns.are.complex.
Tropical cyclones increases.in.intensity,.particularly.in.north.
Pacific,.indian.ocean,.and.southwest.Pacific
increase.in.intensity..changes.in.frequency.
and.track.are.uncertain
Glaciers and
snow cover
decrease.in.mass.of.glaciers,.but.not.in.all.
regions..decrease.in.snow.cover.in.regions.in.
the.northern.Hemisphere..earlier.peak.runoff.
from.glacier.and.snowmelt.
continued.decrease.in.glacial.mass.and.
snow.cover
Sea level increased.about.0.2.meters.over.the.20th.
century..A.rise.equivalent.to.0.3.meters.per.
century.was.recorded.since.the.early.1990s,.
but.it.is.not.clear.if.this.is.an.acceleration.of.
long.term.sea.level.rise
iPcc.projects.0.2.to.0.6.meters.by.2100,.
but.upper.end.could.be.much.higher.
Source: derived.from.iPcc,.2007a;.kevin.trenberth,.national.center.for.Atmospheric.research..Personal.communication..may.19,.2008;.trenberth.et.al.,.2003.
xviii
are.often.referred.to.as.an.intensification and acceleration of the hydrologic cycle..the.result.of.hydrologic.change.and.increased.variability.is.shorter.periods.of.more.intense.rainfall,.and.longer.warmer.dryer.periods..the.table.below.summarizes.the.observed.trends.and.projections.for.the.21st.century.of.key.hydrologic.variables..increase.in.variability.and.intensification.of.hydrologic.processes.is.evident.
The impact of climate change varies with hydrology/climate regime and water use sectors..in.some.climatic.regions.(such.as.parts.of.lcr.and.ecA),.glacier.and.snowmelt.define.hydrology.while.in.other.parts.of.the.world,.precipitation.is.the.driving.factor.(for.example.much.of.AFr)..the.impact.of.climate.change.on.snow-driven.hydrology.is.quite.different.from.rainfall-driven.hydrology..in.snow-driven hydrology,.changes.in.the.pattern.of.precipitation.and.the.associated.acceleration.of.snow.and.glacier.melt.from.rising.temperatures.are.projected.to.significantly.affect.runoff.and,.consequently,.water.available.for.human.consumption,.agriculture.and.energy.generation..changes.in.the.timing.of.runoff.can.cause.increased.flooding,.failure.of.storage.infrastructure,.landslides,.and.loss.of.surface.soil..in.systems.fed.by.snowmelt.it.is.generally.the.shape.(volume).and.timing.of.the.runoff.that.matters..Hydrologic.variability—while.always.present—is.more.predictable.and.so.less.significant..in.contrast,.in.rainfall-driven hydrology,.flood.and.drought.cycles.are.much.less.predictable.and.their.magnitude.(severity).has.a.significant.impact.on.water.availability.(quantity,.quality,.and.timing).for.water.supply.and.sanitation,.agricultural.production.(yield,.growing.season),.energy.(hydropower),.and.environmental.sustainability..climate.change.will.exacerbate.the.uncertainty.and.severity.of.hydrologic.variability..regardless.of.the.hydrologic.regime,.the.impact.of.hydrologic.variability.and.climate.change.on.coastal.regions.(particularly.in.eAP,.sAr.and.the.caribbean).is.expected.to.be.significant.through.sea.level.rise.on.the.sea-side.and.increased.flooding.from.the.land-side.
Climate change could profoundly alter future patterns of both water availability and use, thereby increasing global levels of water stress. direct.effects.of.climate.change.on.water.resources.and.availability.as.a.result.of.changes.in.hydrology.is.shown.above..less.is.known.about.the.impacts.of.climate.change.on.groundwater.availability,.including.interactions.with.surface.water..there.is.also.relatively.little.information.on.the.impact.on.water.quality.and.aquatic.systems..the.potential.changes.in.water.availability.and.use.may.aggravate.global.‘water.stress’..most.studies.have.found.that.levels.of.water.stress.will.increase,.although.there.are.significant.differences.in.estimates..Arnell.(2004)—who.accounts.for.population.growth.and.the.impact.of.climate.change—found.that.the.number.of.people.projected.to.experience.an.increase.in.water.stress.is.between.0.4.to.1.7.billion.in.the.2020s.and.between.1.and.2.7.billion.in.the.2050s.(using.the.A2.population.scenario.for.the.2050s)..when.environmental.flow.needs.are.incorporated—that.is,.the.amount.of.water.required.to.sustain.a.functioning.ecosystem—the.degree.of.water.stress.is.projected.to.increase.even.further.(smakhtin.et.al,.2003).
Future water availability and use will also depend on non-climatic factors..climate.change.is.only.one.of.many.factors.that.will.determine.future.patterns.of.water.availability.and.use..in.the.absence.of.policy.changes,.non-climatic.factors.are.likely.to.aggravate.or.attenuate.the.adverse.effects.of.climate.change.on.water.availability.and.quality,.as.well.as.have.a.significant.influence.on.water.demand..Population.growth.and.economic.development.will.play.a.dominant.role..non-climatic.impacts.could.be.generated.through.many.realms—from.population.growth,.migration.and.income.to.technologies.and.infrastructure.to.land-use.patterns.and.agricultural.activities/irrigation..such.non-climatic.drivers.could.dwarf.the.impacts.attributed.to.climate.change.alone..changes.in.policies,.legislation.and.management.could.induce.additional.and.substantial.effects.on.water.demand.and.water.availability.(quantity.and.quality),.in.a.positive.or.negative.direction.
xix
water sector is highly exposed to climate change with implication beyond the sector
The impacts of a changing climate will be felt in developed and developing countries alike. However, many parts of the developing world are particularly vulnerable..vulnerability.to.climate.change.has.been.defined.by.iPcc.as.the.degree.to.which.geophysical,.biological.and.socioeconomic.systems.are.susceptible.to,.or.unable.to.cope.with,.adverse.effects.of.climate.change,.including.climate.variability.and.extremes..it.is.a.function.of,.amongst.others,.the.character,.magnitude.and.rate.of.climate.variation.to.which.a.system.is.exposed,.its.sensitivity.and.its.adaptive.capacity..within.the.water.sector,.a.number.of.additional.factors.make.many.developing.countries—and.the.poorest.within.them—particularly.vulnerable.to.the.potentially.adverse.impacts.of.climate.change. these.include.weak.institutions.and.limited.institutional.capacity,.high.levels.of.poverty,.insufficient.stock.of.water.management.and.services.infrastructure,.lack.of.access.to.technology.and.capital.to.invest.in.risk.reduction,.and.dependence.on.climate-sensitive.sectors.such.as.agriculture,.forestry.and.fisheries.
Water investments are particularly vulnerable to impacts of climate change through the hydrologic drivers. climatic.impacts.will.have.significant.consequences.on.investments.in.water.systems.(or.infrastructure).associated.both.with.delivering.water.services.and.with.managing.water..water.systems.for.delivering.water.services.include.irrigation;.urban.water,.sanitation.and.drainage;.rural.water.and.sanitation;.and.ports.and.navigation..systems.for.managing.water.resources.include.those.for.delivery.of.bulk.irrigation,.watersheds,.and.water.resources.broadly,.as.well.as.multi-purpose.systems.(including.hydropower).and.flood.control..For.example,.in.urban.environments,.more.heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and.water.and.wastewater.treatment.facilities;.sea.level.rise.could.lead.to.salinisation.of.water.supplies.from.coastal.aquifers..climate.change.could.increase.irrigation.demand.due.to.the.combination.of.decreased.rainfall.and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation.systems.that.are.in.many.cases.already.under.performing..changes.in.river.flows.have.a.direct.impact.on.hydropower.generation..soil.erosion.from.increased.rainfall.intensity.could.affect.watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation.of.multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the.infrastructural.and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even.national.boundaries..the.term.‘system’.and.‘infrastructure’.are.used.interchangeably.in.this.report.to.capture.all.elements—physical.infrastructure,.management.institutions,.and.financial.aspects—that.contribute.to.the.performance.of.the.intended.function.of.water.investments.
The extent to which each water system will be impacted by climate change will depend on its degree of vulnerability, including internal capacity to adapt..However,.the.potential.impacts.of.climate.change.are.real,.and.may.extend.far.beyond.the.water.sector..For.example,.pressure.on.water.supply.and.sanitation.facilities.could.have.a.wide.range.of.adverse.effects.on.human.health..reduced.availability.of.water.for.irrigation.could.threaten.food.security,.rural.development,.and.the.economies.of.countries.that.are.largely.dependent.on.the.agricultural.sector..reduced.water.for.hydropower.generation.(or.increased.fluctuations.in.river.flows).could.decrease.electricity.grid.stability.and.reliability,.with.consequent.effects.on.the.economy..managing.sedimentation.(e.g.,.through.flushing).could.affect.the.timing,.supply.and.quality.of.water.to.the.various.sectors.served.by.a.multi-purpose.system,.with.impacts.felt.in.the.larger.economy..in.the.worst.case,.competition.over.limited.water.resources.across.sectors.and.nations.could.worsen.hostility.and.mistrust,.and.increase.conflicts.over.water.
xx
Water-dependent sectors are affected by the impact of climate change on the water sector. in.most.countries,.water.use.has.increased.in.recent.decades..sectoral.water.use.patterns.can.be.expected.to.continue.to.change.over.time.in.response.to.non-climatic.drivers,.in.addition.to.water.resource.management.and.delivery.systems..this.includes.not.only.infrastructure.and.technology,.but.also.institutions.that.govern.water.use.within.sectors.(e.g.,.water.pricing),.amongst.sectors.(e.g.,.water.trading),.and.even.across.national.boundaries.(e.g.,.transboundary.river.basin.agreements)..in.the.future,.climate.change.could.also.impact.water.using.sectors,.affecting.both.the.amount.and/or.quality.desired.(on.the.demand.side).and/or.the.extent.to.which.demands.are.met.(on.the.supply/availability.side)..it.is.important.to.emphasize.that.changes.in.variability.could.be.as.important.as.changes.in.long-term.averages,.particularly.if.water.is.not.withdrawn.from.groundwater.bodies.or.reservoirs.
International basins can be at risk due to climate change..over.270.international.rivers.are.shared.by.some.90%.of.the.world’s.nations.and.territories..transboundary.river.basins.and.shared.rivers.present.both.challenges.and.opportunities.for.cooperation.and.growth..developed.economies,.in.europe.and.north.America,.have.in.most.cases.achieved.a.relative.equilibrium.in.managing.transboundary.basins.for.best.return.on.hydrology.through.transboundary.institutional.arrangements,.including.treaty.regimes.dealing.with.issues.of.river.infrastructure.and.the.quantity.and.quality.of.water.flows,.as.well.as.infrastructure.to.manage.variability.and.extreme.events..increasingly,.cooperative.efforts.are.focusing.on.the.sharing.of.benefits,.rather.than.water..the.developing.economies.sharing.river.basins.remain.challenged.by.lack.of.weak.institutional.arrangements.and.inadequate.infrastructure.for.optimum.benefit..regardless.of.the.level.of.economic.development,.climate.change.poses.a.threat.to.transboundary.basins..evidence.suggests.that.the.challenges.and.conflicts.among.the.riparian.states.depend.on.the.degree.of.variability.and.uncertainty.associated.with.the.resource.availability..Projected.changes.in.water.resources.variability.due.to.climate.change.can.impact.the.water.balance.and.consequently.the.hydropolitical.balance.in.transboundary.basins..Administrative.instruments.for.transboundary.basins,.such.as.treaties.and.agreements.should.be.reviewed.for.impact.of.climate.change.with.adaptation.measures.explored.and.negotiated.in.advance.
The current financial crisis and various sector crises have and will continue to impact financing of adaptation to climate change..A.theme.that.has.been.emphasized.throughout.this.report.is.that.climate.change.is.not.the.only—or.even.the.primary—factor.exerting.stress.on.the.water.sector,.and.by.extension.societies,.economies,.and.the.environment..the.current.financial.crisis.and.the.sector.crises.(e.g.,.rising.food.prices,.energy.cost).have.forced.many.governments.in.developing.countries.to.defer.urgent.operation.and.maintenance,.as.well.as.water.investment.needs..in.the.near-.to.medium-term,.the.situation.is.expected.to.worsen.unless.investment.funds.are.channeled.to.the.water.sector..Here,.a.combination.of.the.new.financial.and.climate.change.architectures.such.as.the.vulnerability.Fund,.the.climate.investment.Fund,.and.other.mechanisms.to.alleviate.the.investment.bottle.neck.should.be.made.available.to.the.client.bank.countries..viewed.in.the.long.term,.the.current.financial.crisis.and.the.stimulus.packages.to.respond.to.this.crisis.can.be.designed.to.take.into.account.the.wider.risk.of.climate.change.in.the.recovery.and.rebuilding.process.
world bank water investments and climate change
Climate change poses risk to World Bank investments in the water sector..A.review.of.the.water.portfolio.was.undertaken.to.understand.the.composition.of.the.bank.water.investments.and.their.exposure.to.climate.change..bank’s.investments.in.the.water.sector.over.the.period.fiscal.
xxi
years.2006–2010.are.reviewed.for.class.of.investment—water.services.delivery.or.water.resources.management—and.climate.change.content.of.the.project..this.particular.period.offers.sufficient.number.of.approved.and.pipeline.projects.for.review.during.a.time.frame.that.climate.change.is.high.in.the.bank’s.agenda..Additionally,.exposure.of.bank’s.water.investment.to.current.hydrologic.variability.and.future.climate.change.were.assessed.using.hydrology.projections.at.a.scale.and.resolution.useful.in.water.planning.and.design.
The water portfolio reviewed consists of 191 projects approved in 83 countries during FY06–08 for net commitments of $8.8 billion. the.regions.that.invested.the.most.in.water.relative.to.their.total.regional.investment.are.mnA.(14%).and.sAr.(14%).and.the.region.that.invested.the.least.is.lcr.(8%)..the.share.of.water.lending.relative.to.the.overall.world.bank’s.investments.increased.from.8%.in.Fy06.to.12%.in.Fy08..the.pipeline.of.projects.for.Fy09–10.consists.of.220.projects.corresponding.to.a.volume.of.us$11.3.billion..it.should.be.noted.that.not.all.the.projects.in.the.pipeline.will.be.approved.by.end.of.Fy10..the.two.figures.below.show.these.investments.by.geographic.location,.volume,.and.type—services/resource.management.
The water portfolio is dominated by projects that primarily deliver water services..For.the.Fy06–08.period.lending.for.water.services.consist.of.70%.of.the.lending.volume.for.63%.of.the.projects..the.largest.investment.in.water.services.systems.is.in.eAP.($1,327.million),.sAr.($1,241.million).and.AFr.($1,128.million).regions..For.this.period,.highest.lending.in.water.resources.is.in.AFr.($926.million),.followed.by.sAr.($703.million).and.eAP.($364.million)..implication.of.climate.change.on.these.investments.would.be.different.as.the.driving.hydrologic.conditions.are.different.
Review of the content of the portfolio suggests an increasing level of attention to climate change..the.review.of.water.projects.for.inclusion.of.mitigation.and.adaptation.measures.shows.that.out.of.191.active.projects.approved.in.Fy06–08,.35%.(67.projects).considered.strategies.
Distribution of World Bank water projects for FY06–08 (active) and FY09–10 (pipeline)
Source: world.bank,.2009.
xxii
to.reduce.the.impacts.of.climate.variability.and.change,.including.adaptation.and/or.mitigation.measures..of.the.67.projects.with.some.strategy,.58%.are.related.to.adaptation,.31%.related.to.mitigation.and.10%.related.to.both..the.water.sector.projects.are.primarily.focused.on.adaptation..For.the.active.portfolio,.20%.of.the.projects.addressed.climate.variability.and.change.through.adaptation.measures..of.the.20%.of.projects.taking.adaptation.measures,.it.is.important.to.note.that.these.measures.address,.for.the.most.part,.strategies.to.reduce.vulnerability.to.climate.variability.rather.than.considering.the.long-term.effects.of.climate.change..of.the.total.number.of.projects.at.the.regional.level,.lcr.had.the.largest.portfolio.with.possible.adaptation.measures.(28%).followed.by.sAr.(25%).and.mnA.(25%)..Pipeline.shows.an.increased.attention.to.the.adaptation.agenda.for.most.regions..overall,.there.is.clearly.a.higher.level.of.awareness.among.the.bank.and.client.countries.towards.climate.change.and.climate.variability.issues.
Projections of key hydrologic indicators for water planning
A common set of hydrologic indicators are projected for 2030 and 2050 for Bank regions. these.are:.runoff,.basin.yield,.high.and.low.flows.(floods.and.droughts),.minimum.base.flow.(a.proxy.for.shallow.groundwater.movement),.and.net.irrigation.demand..these.indicators.are.projected.at.the.catchment.level,.most.appropriate.scale.for.water.planning.and.investment..the.methodological.approach.used.for.this.analysis.was.designed.to.capture.the.full.spectrum.of.gcm.climate.projections..twenty-two.gcms.along.with.three.emissions.scenarios.(b1,.A1b,.A2).are.used.to.analyze.changes.in.the.key.hydrologic.variables.in.the.years.2030.and.2050.from.historical.values.in.1961–1990..in.this.analysis,.gcm.output.is.used.as.input.to.the.hydrologic.model.clirun-ii.(strzepek,.et.al,.2008),.developed.specifically.to.assess.the.impact.of.climate.change.on.runoff.and.to.address.extreme.events.at.the.annual.level.by.modeling.low.and.high.flows..this.analysis.advances.an.earlier.and.much.referenced.effort.by.milly,.et.al.(2005)..clirun-ii.is.stand-alone.hydrologic.model.designed.for.application.in.water.resource.projects.and.generates.output.at.a.0.5.x.0.5.degree.grid.scale,.aggregated.to.approximately.2.x.2.degree.
Water investments by volume and category (services/resource management)
Source: world.bank,.2009.
xxiii
resolution..the.entire.projection.set.reflecting.the.historical.baseline.conditions.and.projections.for.2030.and.2050.is.now.available.for.all.bank.regions.
In the context of downscaling, relying on results from a single or even just a few GCMs is not advisable..care.needs.to.be.taken.in.selecting.a.method..beyond.reproducing.the.underlying.uncertainties.of.gcms,.many.introduce.additional.uncertainty.and.biases..this.is.because.there.
Climate Moisture Index: Range of CGMs for three emission scenarios for various regions
CMI Historic and Range of 2050 Climate Change Impacts
–0.1
0
–0.2
–0.3
–0.4
–0.5
–0.6
–0.7
–0.8
–0.9
A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1
–0.18
–0.2
–0.22
–0.24
–0.26
–0.28
–0.3
–0.32
–0.34
A2 A1b B1 A2 A1b B1 A2 A1b B1
LegendTop of box: 25th percentile Red line: median CMIBottom of box: 75th percentile Dashed line: historical CMI (1960–1990)Whiskers: extreme CMI values Cross hairs: model outliers
EAP
ECALCR
SAR
MNA
AFR
Globe
WB RegionsNon WB
xxiv
are.model.errors.in.any.one.model.and.natural.variability.(randomness).in.any.particular.run..A.single.model,.if.run.multiple.times.with.differing.initial.conditions,.can.provide.an.estimate.of.the.uncertainty.due.to.natural.variability..However,.for.any.given.model,.there.are.also.uncertainties.associated.with.the.assumptions.made.about.model.physics.and.parameterizations,.as.well.as.with.the.structural.aspects.of.the.model.itself..using.a.group.of.gcms.(multi-model.ensembles),.as.opposed.to.one.individual.gcm,.can.account.for.biases.and.errors..the.use.of.multi-model.ensembles.raises.the.question.of.how.to.capture.the.full.range.of.results.from.model.runs.
Climate Moisture Index characterizes the projected climate conditions. the.calibrated.historical.model.simulations.and.all.of.the.22.gcm.projections.for.the.three.emissions.scenarios.for.2030.and.2050.are.analyzed..the.climate.condition.was.categorized.by.the.projected.level.of.moisture.(or.aridity).using.the.climate.moisture.index.(cmi)..the.box.and.whiskers.plots.on.the.previous.page.show.the.climate.moisture.index.projection.for.2050.for.bank.regions,.as.well.as.other.regions..the.height.of.the.box.indicates.the.degree.of.variability.which.results.from.the.
Projected percent change in hydrologic indicators for 2030 from 1961–1990 baseline
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
RunoffBasin Yield
Low Flow
High Flow
Irrigation Deficit
Base Flow
xxv
differences.in.means.between.different.climate.models..For.example,.in.the.lcr,.75%.of.the.gcms.indicate.drying.with.all.3.scenarios..the.cmi.for.the.sAr.has.the.largest.spread.because.of.the.way.the.different.gcms.model.the.monsoons..in.mnA,.there.is.little.variation.because.the.area.is.so.dry..note.that.the.land-based.cmi.projections.for.the.bank.regions.are.more.negative.than.non-bank.regions.(e.g.,.oecd)..However,.the.relative.aridity.(compared.with.the.historical).for.both.bank.and.non-bank.regions.remains.the.same.
Projections at the catchment level allow for analysis of inter-regional variation at the project planning scale. Hydrologic.indicators.mapped.for.the.bank.regions.for.the.middle.climate.condition.are.shown.in.the.figure.on.page.xxiv..the.general.pattern.is.consistent.with.projections.of.runoff.made.directly.from.climate.model.runs..Here,.specific.indicators.provide.a.deeper.and.more.water-specific.insight.regarding.potential.changes.in.the.water.availability.and.distribution.for.various.uses.and.by.various.water.infrastructure.interventions..For.each.region,.detailed.information.for.each.of.these.indicators.is.available.at.the.0.5.x.0.5.degree.resolution,.as.
Projected exposure map by hydrologic drivers (2030)
Low Medium High
Low Medium High
Low Medium High
Low Medium High
Low Medium High
Low Medium High
RunoffBasin Yield
Low Flow
High Flow
Irrigation Deficit
Base Flow
xxvi
well.as.aggregated.at.the.catchment.level..it.is.planned.that.this.information.will.be.available.via.a.web-based.interface.
exposure of the bank investment to climate change
The World Bank’s investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide.some.sense.of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they.represent..using.threshold.criteria.for.changes.in.each.indicator,.maps.were.created.for.high,.medium,.and.low.exposure.categories.for.each.indicator.(see.figure.page.xxv)..water.projects,.classified.by.water.systems,.are.superimposed.on.the.appropriate.exposure.map..the.outcome.is.an.exposure.categorization.of.each.water.system.according.to.its.respective.indicator..in.this.analysis,.exposure.to.the.impact.of.climate.change.for.the.following.water.systems.on.the.bank.portfolio.is.assessed:.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation,.flood.control,.river.basin.management,.and.multi-purpose.(supply.water.for.multiple.purposes)..results.of.the.potential.exposure.of.the.active.bank.water.investments.were.they.to.operate.in.2030.and.2050.are.available.
The following bar charts show the level of exposure of the Bank water investments to climate change by volume of investment and number of projects by region and Bank-wide..similar.charts,.categorized.by.water.systems,.are.available.for.each.region.and.bank-wide.
Projections indicate that about half of the Bank water projects reviewed would potentially be at high to medium level of exposure to climate change impacts in 2030..within.each.regional.portfolio,.eAP.shows.close.to.two-third.of.projects.with.potential.exposure.to.high/medium.risk,.possibly.due.to.increased.flooding..AFr.and.lcr.show.about.half.of.the.projects.and.mnA.some.40%.at.potential.high.to.medium.risk.of.exposure..ecA.and.sAr.show.about.one-third.of.the.projects.at.potential.risk.of.exposure.to.hydrologic.changes..Projections.for.2050.show.exposure.increasing.for.all.regions.except.eAP..obviously,.the.level.of.
Potential exposure of water projects to climate change in 2030 and 2050
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Bank
wid
e
2030
% o
f wat
er p
roje
cts
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Bank
wid
e2050
% o
f wat
er p
roje
cts
MedLow High
xxvii
uncertainty.related.to.projecting.climate.change.so.far.in.time.would.be.too.high.to.make.much.of.this.difference.
In terms of investments, about half of the total water investments (including the pipeline) are projected at high/medium exposure level to climate change impacts in 2030..this.translates.to.approximately.$10.billion.on.the.Fy06–10.water.projects.reviewed.here,.risk.associated.with.approval,.delay,.or.drop.of.pipeline.projects.notwithstanding..the.pattern.of.risk.of.exposure.of.investment.roughly.follows.that.of.the.projects..For.2050,.climate.change.projections.show.an.increase.in.mnA,.AFr,.lcr,.and.ecA,.while.expected.to.decrease.in.eAP,.and.sAr..Again,.the.uncertainty.associated.with.the.climate.change.projections.in.2050.is.considered.quite.high.and.therefore.this.conclusion.should.be.viewed.with.caution.
Climate-smart investments must explicitly consider risk
Climate change projections contain a great deal of uncertainty and their use requires special care..the.best.available.science.is.used.here.to.assess.the.exposure.of.the.bank’s.water.investments.to.the.potential.impact.of.hydrologic.variability.and.climate.change..none-the-less,.substantial.uncertainty.remains.regarding.the.real.effects.of.climate.change..there.have.been.major.advances.in.projecting.the.impacts—both.from.general.circulation.models.and.downscaling/statistical.methods—which.allows.reporting.general.trends.with.some.degree.of.confidence.(including.in.temperature,.precipitation,.and.extreme.events)..However,.there.are.still.significant.unknowns,.and.even.more.challenging.“unknown.unknowns”..there.is.no.way.around.these.uncertainties.given.the.current.state.of.the.science—even.agreement.on.a.particular.phenomenon.across.multiple.models.does.not.‘prove’.that.a.given.climate.projection.will.indeed.come.to.pass.
Reducing water sector’s vulnerability to climate change means managing water under conditions of uncertainty. water.professionals.have.always.dealt.with.and.accounted.for.risk.
Potential exposure of water investments to climate change in 2030 and 2050
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Bank
wid
e
2030
% o
f wat
er p
roje
cts
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Bank
wid
e
2050
% o
f wat
er p
roje
cts
MedLow High
xxviii
and.uncertainty,.but.climate-change.related.uncertainties.will.require.water.to.be.managed.fundamentally.different.than.in.the.past..Historically,.water.planning.was.carried.out.under.the.key.assumption.of.a.stationary.hydrologic.pattern:.the.mean,.variance.and.standard.deviation.of.hydrologic.time.series.fixed.over.time—commonly.known.as.stationarity.of.hydrology..this.assumption.is.no.longer.considered.valid,.forcing.decision-makers.to.estimate.hydrologic.risks.to.water.systems.under.even.more.uncertain.conditions..the.only.viable.approach.in.most.investment.cases.is.explicit.consideration.of.risk.and.probability.of.occurrence.of.extreme.events.
Water investments require a formal risk-based analysis in all aspects of the project/program cycle..water.systems.are.subject.to.both.climate.and.non-climate.related.stresses,.but.there.are.certain.types.of.water.investments.where.uncertainties.related.to.climate.change.could.have.a.significant.impact,.and.so.particular.care.needs.to.be.taken.in.undertaking.a.detailed,.rigorous.risk.assessment..these.include.highly.capitalized.or.unique.projects,.irreversible.investments,.engineering.structures.with.long.lifetimes,.long-lived.benefits.and.costs,.etc..examples.include:.multi-purpose.hydraulic.infrastructure,.interbasin.water.transfer.schemes,.water.conveyer.systems.for.irrigated.agriculture,.regional/transboundary.investments..yet,.there.are.water.systems.that.are.inherently.resilient.to.some.degree.of.hydrologic.variability.and.climate.change,.are.not.significantly.impacted,.or.the.consequents.of.impact.can.be.readily.remedied..in.these.cases,.a.less.rigorous.risk.assessment.(screening.level).may.be.sufficient.
Given the policy and financial implications of making water investment decisions, a more systematic approach is needed..risk-based.decision.making.is.the.systematic.consideration.of.the.probabilities,.consequences,.and.values.associated.with.different.decision.alternatives..in.general,.risk-based.approach.involves.the.following.general.stages:.project.objectives.definition.and.characterization.of.the.system.components;.knowledge.of.the.likelihood.and.consequences.of.adverse.events.that.could.compromise.those.objectives;.identification.of.the.options.for.adapting.the.system.or.project.to.render.it.less.vulnerable.in.the.face.of.the.identified.risks;.and.assessment.(either.quantitatively.or.qualitatively).of.adaptation.options.
A special class of diagnostic indicators is used for the analysis of specific water resource systems or system design configurations and performance..several.measures.of.system.performance.have.been.proposed.that.permit.the.evaluation.of.a.specific.design.configuration.over.a.range.of.system.inputs.and.service.levels..each.indicator.is.based.on.the.probability.that.a.system,.characterized.by.a.given.set.of.design.parameters,.will.provide.the.intended.level.of.services.under.a.range.of.dynamic.inputs.and/or.demand.conditions..the.measures.of.system.performance.are.defined.over.a.sequence.of.discrete.time.periods..within.each.period,.the.system.either.performs.(provides.an.acceptable.level.of.services).or.fails.to.do.so..these.indicators.are:.reliability;.resiliency;.vulnerability;.and.robustness.
Potential adaptation options can be categorized into those that carry ‘no regrets’ and those that are ‘climate justified’. many.of.the.options.to.reduce.vulnerability.to.climate.variability.are.no.different.in.a.world.with.climate.change.than.they.are.in.a.world.without..these.include.demand.management.measures.to.increase.water.use.efficiency.and.productivity,.such.as.water-conserving.irrigation.technologies;.wastewater.recycling;.economic.incentives,.including.water.pricing;.and.the.encouragement.of.water.markets.that.move.water.to.high-valued.uses..they.also.include,.for.example,.measures.to.improve.early.warning.systems.and.risk-spreading.(e.g.,.disaster.insurance)..these.options.carry.‘no regrets’.in.that.they.would.generate.net.social.and/or.economic.benefits.irrespective.of.whether.or.not.anthropogenic.climate.change.occurs..on.the.
xxix
other.hand,.other.actions.might.only.be.justifiable.under.man-made.change.in.climatic.variability..‘Climate justified’.measures.may.include,.for.example,.constructing.new.infrastructure.(dams,.water.conveyance.systems,.irrigation.systems),.retro-fitting.existing.infrastructure,.changing.rules.of.operation,.tapping.new.sources.of.water.(e.g.,.desalinization),.water.transfers,.conjunctive.use.of.surface.and.groundwater,.innovative.demand.management,.etc..However,.many.of.these.measures.may.be.of.the.‘no-regrets’.type.depending.on.the.specific.circumstances..whether.they.belong.to.one.or.the.other.category.will.have.to.be.determined.on.a.case.by.case.basis.
The distinction between ‘no regrets’ and ‘climate-justified’ options is important in near-term and long-term decision making..For.“no.regrets”.options,.uncertainties.in.projections.are.to.a.large.extent.immaterial..by.definition,.these.actions.should.be.taken.in.order.to.meet.current.economic,.social.and.environmental.objectives,.but.they.also.serve.the.dual.purpose.of.reducing.vulnerabilities.to.future.climatic.conditions..it.is.in.the.realm.of.the.‘climate-justified’.that.water.managers.will.have.to.make.difficult.decisions.about.how.to.balance.the.political,.economic,.social.and.environmental.costs.of.action.versus.of.non-action,.given.an.uncertain.future..it.is.in.this.context.that.the.indicators.of.performance.listed.above.are.used..the.options.selected.should.include.plan.and.design.for.more.resilient.water.interventions..the.systems.designed.must.be.‘intelligent’.and.robust.in.the.sense.that.they.are.able.to.deliver.(near).optimal.levels.of.service.or.management.over.a.range.of.conditions,.including.through.relatively.modest.re-design,.retrofitting.or.re-operation..implicit.in.robustness.is.also.flexibility,.that.is,.the.ability.to.anticipate.and.react.to.a.wider.and.largely.unknown.range.of.future.climatic.conditions.
There is a certain class of projects for which risk-based analysis would be particularly essential..climate.change.will.affect.most.water.systems.to.some.degree..However,.some.water.services.or.resources.by.their.very.nature.are.more.vulnerable.to.climate.change.than.others..For.example,.small.or.distributed.water.supply.systems.that.can.easily.make.incremental.changes.at.low.cost.are.vulnerable.to.climate.change,.but.may.face.less.exposure.to.changes.in.climate,.may.be.less.sensitive.to.climate.changes,.or.may.have.sufficient.adaptive.capacity.to.manage.those.changes..the.systems.listed.below,.however,.are.particularly.vulnerable.and.special.care.should.be.taken.to.flag.such.water.investments.for.risk-based.analysis..these.systems.would.likely.be.designed.differently.if.climate.change.were.taken.into.account,.and.failing.to.take.climate.change.into.account.likely.would.cause.significant.economic.loss.(Hobbs,.et.al.1997).
•.Highly.capitalized.or.unique.projects•.engineering.structures.with.long.lifetimes•.multi-purpose.infrastructure.systems•.long-lived.benefits.and.costs•.systems.susceptible.to.climate.anomalies.or.extreme.events•.urban.water.supply
way forward
Insight into the various dimensions of water and climate change has identified the gaps and guides the next steps. As.the.world.bank.water.agenda.mainstreams.adaptation.to.the.impact.of.climate.change,.the.questions.raised.in.this.report.will.continue.to.be.an.integral.part.of.the.ongoing.work..these.questions.are:.(i).what.are.the.impacts.of.climate.variability.and.change.on.water.systems,.both.natural.and.engineered;.(ii).what.are.adaptation.strategies.to.reduce.vulnerability.of.water.systems.to.these.impacts;.and.(iii).how.can.the.bank.assist.client.countries.in.making.informed.decisions.regarding.adaptation.options.in.their.water.investments?
xxx
in.order.to.address.these.questions.the.following.actions.will.guide.the.bank’s.water.practice:.(i).continued.strengthening.of.the.analytical.foundation,.(ii).explicit.incorporation.of.hydrologic.variability.and.climate.resiliency.in.project.preparation.and.other.bank.operations.(iii).a.strengthening.of.bank.expertise.on.water.and.climate.change.
in.particular.it.is.foreseen.that:.(i).the.water.Anchor.will.up-date.the.projections.of.the.hydrologic.drivers.for.water.investment.presented.in.this.report.on.a.regular.basis.and.make.them.more.readily.available.for.the.regional.staff.for.use.through.guidelines,.notes,.web-page.etc..(ii).jointly.with.the.regions.there.will.be.a.further.expansion.and.formalization.of.a.risk-based.approach.to.adaptation.related.investments.(iii).guidelines.will.be.provided.for.improved.decision.making.by.explicit.incorporation.of.climate.change.effects.in.project.economic.analysis.and.through.the.preparation.of.assessments.of.the.cost.of.adaptation.and.measures.to.reduce.vulnerability.at.the.river.basin.level.
Finally,.in.the.future.more.work.is.needed.on.the.impact.of.climate.change.on.social.and.economic.development.
1
CHaPTer 1: ConTexT and overview
introduction
Evidence of increased hydrologic variability and climate change is solid..the.intergovernmental.Panel.on.climate.change.has.concluded.that.there.is.increasing.evidence.that.the.earth’s.climate.is.changing.and.at.an.unprecedented.rate.(iPcc,.2007a)1..this.is.contributing.to.increased.frequency.and.magnitudes.of.extreme.events,.including.both.floods.and.droughts.(e.g.,.2007–8.floods.in.south.and.east.Asia,.2006–7.droughts.in.parts.of.Africa.and.middle.east,.200–009.drought.in.Australia)..Accelerated.glacial.melt.has.been.documented.in.the.Andes.in.south.America,.the.Himalayas.in.Asia,.and.even.on.mt..kilimanjaro.in.east.Africa..sea.level.rise.is.already.threatening.many.major.coastal.cities.and.small.islands.
Warming of the climate system in recent decades is ‘unequivocal’ (IPCC, 2007a)..the.earth’s.temperature.is.highly.variable,.with.year.to.year.changes.often.masking.the.overall.rise.of.approximately.0.74°c.that.has.occurred.from.1906–2005..nevertheless,.there.is.a.clear.twentieth.century.upward.trend,.and.in.particular.a.rapid.rise.over.the.past.50.years..indeed,.the.period.from.the.1980s.onwards.has.been.the.warmest.period.in.the.last.2000.years..the.iPcc.has.projected.that.by.the.end.of.the.21st.century,.the.earth’s.average.temperature.is.likely.to.rise.by.between.1.1.and.6.4°c.from.the.mean.in.1990,.depending.on.the.emission.path.
And human activities are in part responsible. greenhouse.gases.that.trap.heat.(water.vapor,.carbon.dioxide,.and.methane).exist.naturally.in.the.atmosphere..However,.there.is.increasingly.strong.evidence.that.‘anthropogenic.forcings’—and.in.particular.increasing.concentrations.of.co2.from.the.burning.of.fossil.fuels—have.contributed.to.global.warming..According.to.the.iPcc,.most.of.the.observed.increase.in.global.temperatures.since.the.mid-20th.century.is.very.likely.due.to.the.observed.increase.in.anthropogenic.greenhouse.gas.concentrations.(iPcc,.2007a)..this.also.holds.at.the.continental.scale.for.all.regions.except.Antarctica.
Responses to climate change take two linked tracks—mitigation and adaptation. mitigation.seeks.to.minimize.the.human.footprint.through.efforts.to.control,.reduce.or.even.eliminate.greenhouse.gas.emissions..this.is.generally.referred.to.as.a.transition.to.low.or.constrained.carbon.growth..examples.include.the.introduction.of.low-carbon.technologies.for.electricity.generation.and.transport,.reforestation,.and.capturing.and.sequestering.emissions..because.the.effects.of.historical.greenhouse.gas.emissions.cannot.be.reversed,.attention.is.increasingly.being.given.to.the.need.for.adapting.to.a.changing.climate..Adaptation.attempts.to.reduce.the.vulnerability.of.human.livelihoods,.economies,.and.natural.systems.to.the.impact.of.climate.induced.changes..examples.include.(a).increasing.the.resiliency.of.the.agricultural.sector.to.droughts.and.reducing.the.risk.of.floods.through.improved.storage.and.infrastructure.management.and.(b).protecting.freshwater.ecosystem.functions.by.integrating.environmental.flow.requirements.in.infrastructure.planning,.design.and.operations..in.some.cases.(e.g.,.hydropower,.wetlands.management).mitigation.and.adaptation.strategies.may.be.closely.linked.and.complimentary.
This report contributes to the World Bank agenda on climate change and more specifically, informs the water sector investments on climate issues, risks and climate-
1AllreferencestoIPCCliteraturecomplywiththespecificcitationformatindicatedbyIPCC.
2
smart adaptation options. using.the.existing.knowledge.and.additional.analysis.commissioned.by.the.world.bank,.the.report.intends.to.illustrate.that.climate.change.is.affecting.the.hydrologic.cycle.and.projections.show.direct.impact.on.the.water.resources.base..depending.on.the.water.investment,.this.impact.can.be.positive,.negative,.or.neutral..the.report.distinguishes.between.stress.on.and.vulnerability.of.the.water.systems.through.use.of.reliability,.resilience,.and.robustness.as.the.key.indicators.of.performance..current.practices.in.the.sector.are.examined.in.order.to.better.understand.the.state-of-the-science.for.incorporating.current.and.future.variability.and.change.in.hydrology.and.climate.in.the.bank’s.portfolio..new.and.innovative.practices.taking.into.account.adaptation.options.for.water.systems.and.risk-based.decision.making.in.water.investments.are.reviewed.and.assessed.for.application.to.major.bank.investments.in.infrastructure..the.climate.change.dimension.is.placed.within.the.context.of.the.impact.of.other.factors.(within.and.outside.the.sector).such.as.population.growth.(and.associated.increase.in.demand).and.land.management,.which.may.be.far.more.significant.and.critical.than.that.of.climate.change.in.some.cases.and.in.some.parts.of.the.world.
Climate Change and the world bank
Climate change is a development issue for the Bank and its clients. wbg.clients,.by.virtue.of.their.geographic.location.and.often.low.coping.capacity,.are.among.the.most.affected..the.bank’s.2007.report.IDA and Climate Change: Making Climate Action Work for Development provides.compelling.evidence.that.the.distribution.of.major.climate-related.risks.around.the.world.is.skewed.against.poor.countries..the.bank’s.2009.development.and.climate.change.strategic.Framework.(dccsF).(world.bank,.2008a).asserts.that.climate.change.is.a.development.issue,.among.others..dccsF.states:.the.anticipated.impacts.of.climate.change,.which.could.begin.to.occur.within.the.next.two.to.three.decades,.include:.dangerous.floods.and.storms.and.more.frequent.and.longer.droughts;.exacerbated.water.stress;.decline.in.agricultural.productivity.and.food.security;.increased.saltwater.intrusion.in.coastal.aquifers.and.estuaries;.increased.stress.on.freshwater.ecosystems;.and.further.spread.of.water-related.diseases,.particularly.in.tropical.areas..this.could.lead.to.population.displacement,.migration,.and.potential.conflicts..in.the.longer.term,.sea.level.rise.and.glacier.melting.threaten.the.existence.of.nations.and.the.development.foundation.of.subcontinents.
Sub-Saharan African countries dominate the list of most climate-affected client countries. other.regions.are.also.affected.by.extreme.events.(e.g.,.south.and.southeast.Asia.flooding,.latin.America.and.south.Asia.rapid.glacial.melt)..climate.change.poses.a.risk.to.world.bank.investments.in.a.wide.range.of.sectors,.including.potentially.undermining.performance,.sustainability.and.contributing.to.water.scarcity.and.water.security.in.certain.cases..this.makes.it.imperative.that.climate.change.adaptation.is.not.separated.from.other.priorities,.but,.rather,.is.integrated.into.development.planning,.programs.and.projects.in.the.client.countries.
Climate change has direct implications for the World Bank’s mission of poverty reduction. the.bank’s.2009.development.and.climate.change.strategic.Framework.(dccsF).states:.“climate.change.threatens.to.reverse.hard-earned.development.gains..the.poorest.countries.and.communities.will.suffer.the.earliest.and.the.most..yet.they.depend.on.actions.by.other.nations..while.climate.change.is.an.added.cost.and.risk.to.development,.a.well-designed.and.well-implemented.global.climate.policy.can.also.open.new.economic.opportunities.to.developing.countries.”.indeed,.developing.countries,.and.particularly.the.poorest.people.in.these.countries,.are.the.most.vulnerable.to.the.adverse.impacts.of.climate.variability.and.projected.climate.change..their.economies.depend.heavily.on.climate-sensitive.sectors.such.as.agriculture,.livestock,.forestry,.
3
fisheries,.water.supply,.and.other.natural.resources..they.are.generally.hindered.by.limited.institutional.capacity.and.access.to.technology.and.capital.to.invest.in.risk.reduction..world.bank.analysis.of.ethiopia,.mozambique.and.kenya.shows.huge.impacts.of.climate.variability.on.the.performance.of.key.economic.sectors.such.as.agriculture,.transport,.energy,.manufacturing,.livestock.and.tourism..estimates.of.the.economic.impacts.of.climate.change.are.likely.to.be.significant,.especially.in.developing.countries.(stern,.2006)..However,.these.can.be.minimized.and.reduced.with.appropriate.adaptation.strategies.
Addressing climate variability through both mitigation and adaptation has been, and continues to be a key priority for the Bank..For.decades,.the.world.bank.has.been.actively.engaged.in.efforts.to.mitigate.climate.variability..the.world.bank.has.provided.countries.with.incentives.to.develop.and.implement.clean.energy.technologies.and.sustainable.transport.systems,.as.well.as.to.improve.practices.in.agriculture,.forestry.and.land.management..this.has.allowed.many.countries.to.achieve.increased.energy.access.for.the.poor.and.improved.livelihoods.for.the.vulnerable,.while.at.the.same.time.moving.towards.a.sustainable,.low-carbon.path.of.development..more.recently.the.focus.has.also.turned.to.adaptation..dccsF.articulates.the.wbg’s.vision.on.how.to.integrate.climate.change.and.development.challenges,.without.compromising.growth.and.poverty.reduction.efforts.through.its.country.operations,.including.policy.dialogue,.lending,.and.analytical.work.in.client.countries,.and.through.its.regional.and.global.operations..A.coordinated.way.to.finance.the.mitigation.and.adaptation.efforts.is.through.the.climate.investment.Funds.(ciFs)..these.funds.are.established.to.serve.as.interim.financing.to.developing.countries.in.addressing.climate.change.issues..the.wbg.is.among.the.multilateral.development.banks.(mdbs).that.will.engage.in.partnership.with.developing.countries.in.their.transition.to.a.carbon-constrained.and.climate.resilient.economies.
Climate change and the water sector
The World Bank is responding by first understanding the risks and impacts, then managing them through climate-smart investments. the.world.bank.recognizes.water.as.a.key.affected.sector..consequently,.the.impact.of.climate.change.and.potential.adaptation.strategies.has.become.central.to.the.dialogue.on.water.policy.reforms.and.investment.programs.with.client.countries..this.has.been.guided.by.climate.change.strategies.prepared.by.each.region.of.the.world.bank.within.the.context.of.the.dccsF..the.2010.world.development.report.focuses,.among.other.factors,.on.the.land.and.water.interface.for.managing.competing.demands.and.creating.new.opportunities.for.climate-smart.development..many.client.countries.in.partnership.with.the.world.bank.group.have.begun.to.take.action.to.adapt.their.water.sector.to.implications.of.climate.change.and.resulting.hydrologic.impacts..this.process.is.supported.by.analytical.and.advisory.assistance.on.water.and.climate.change.carried.out.by.regional.units,.as.well.as.the.water.Anchor..incorporating.climate.change.in.the.portfolio.has.been.steadily.increasing.in.response.to.client.demands..A.number.of.stand-alone.climate.change.projects.have.also.been.financed.through.various.grant.and.lending.instruments.and.they.are.increasing.
There is strong link between changes in climate and the hydrologic cycle..According.to.the.iPcc’s.most.recent.report,.“Observational records and climate projections provide abundant evidence that freshwater resources are vulnerable and have the potential to be strongly impacted by climate change, with wide ranging consequences on human societies and ecosystems.(bates,.et.al,.2008,.p.4)..long-term.trends.in.hydrologic.variables.are.difficult.to.detect.due.to.significant.natural.variability.in.all.components.of.the.hydrologic.cycle.over.both.time.and.
4
space.2.However,.observed.changes.in.the.hydrologic.cycle.at.the.sub-continental.scale.have.consistently.been.associated.with.climate.warming.over.the.past.several.decades..these.changes.are.often.referred.to.as.intensification.and.acceleration.of.the.hydrologic.cycle..these.changes.include.increasing.atmospheric.water.vapor.content;.changing.precipitation.patterns,.intensity.and.extreme.events;.reduced.snow.cover.and.faster.and.widespread.melting.of.ice;.and.changes.in.soil.moisture.and.runoff..it.is.projected.that.many.of.these.phenomena.will.become.more.pronounced.with.climate.change.
Climate change could profoundly alter future patterns of both water availability and use, thereby increasing water stress globally. many.of.the.direct.effects.of.climate.change.on.water.availability.have.been.presented.above..However,.less.is.known.about.the.impacts.of.climate.change.on.groundwater.availability.and.use,.including.interactions.with.surface.water..there.is.also.relatively.little.information.on.freshwater.ecosystems.and.water.quality,.although.according.to.iPcc.(and.other.studies).higher.water.temperatures.and.changes.in.extreme.events,.including.floods.and.droughts,.are.projected.to.affect.water.quality.and.exacerbate.many.forms.of.water.pollution..in.addition,.sea-level.rise.is.projected.to.extend.zones.of.salinisation.of.groundwater.and.estuaries..taken.together,.the.potential.changes.in.water.availability.and.use.may.aggravate.global.‘water.stress’..most.studies.have.found.that.levels.of.water.stress.will.increase,.although.there.are.significant.differences.in.estimates.across.studies..Arnell.(2004)—who.accounts.for.population.growth.and.the.impact.of.climate.change—found.that.the.number.of.people.projected.to.experience.an.increase.in.water.stress.is.between.0.4.to.1.7.billion.in.the.2020s.and.between.1.and.2.7.billion.in.the.2050s.(using.the.A2.population.scenario.for.the.2050s)..when.environmental.flow.needs.are.incorporated—that.is,.the.amount.of.water.required.to.sustain.a.functioning.ecosystem—the.degree.of.water.stress.is.projected.by.some.to.increase.further.(smakhtin.et.al,.2003).3.based.on.these.and.other.studies,.the IPCC concluded with high confidence that, globally, the negative impacts of future climate change on freshwater systems and ecosystems are expected to outweigh the benefits.
Future water availability, use, and investments will also depend on non-climatic drivers, including financial and sector conditions. climate.change.is.only.one.of.many.factors.that.will.determine.future.patterns.of.water.availability.and.use..non-climatic.factors.could.aggravate.or.attenuate.the.adverse.effects.of.climate.change.on.water.availability.and.quality,.as.well.as.have.a.significant.influence.on.water.demand..Population.growth.and.economic.development.(and,.by.extension,.changes.in.lifestyles.and.diets).will.play.a.dominant.role..non-climatic.impacts.could.be.generated.through.many.realms—from.policies.and.legislation.to.technologies.and.infrastructure.to.land-use.patterns.and.agricultural.activities/irrigation..Additionally,.water.infrastructure.investments.are.highly.sensitive.to.the.trends.of.the.official.development.Assistant.(odA),.availability.of.financing.through.multilateral.development.banks.(mdb),.and.the.private.sector.appetite.for.investment..recent.financial.crisis.and.sector.crises.(e.g.,.food,.energy).have.already.shown.their.impact.on.the.water.sector.and.will.continue.to.remain.a.major.challenge..such.non-climatic.drivers.could.dwarf.the.impacts.attributed.to.climate.change.alone,.in.a.positive.or.negative.direction..the.impact.of.the.financial.crisis.on.water.infrastructure.vis a vis.deferred.operation.and.maintenance.can.be.particularly.devastating.
2 Large-scaleatmosphericcirculationpatternsassociatedwithENSO(ElNiño-SouthernOscillation),NAO(NorthAtlanticOscillation)andothervariabilitysystemsthatoperateatwithin-decadalandmulti-decadaltime-scalesareaverystronginfluenceinsomeregions.
3Notethatsuchindicesofwaterstressaretypicallydefinedintermsofannualaveragesanddonotincludevaryinglevelsofwaterquality.
5
Water investments are particularly vulnerable to impacts of climate change. climatic.impacts.will.have.significant.consequences.on.investments.in.water.systems4.(or.infrastructure).associated.both.with.delivering.water.services.and.with.managing.water..water.systems.for.delivering.water.services.include.irrigation;.urban.water,.sanitation.and.drainage;.rural.water.and.sanitation;.and.ports.and.navigation..systems.for.managing.water.resources.include.those.for.delivery.of.bulk.irrigation,.watersheds,.and.water.resources.broadly,.as.well.as.multi-purpose.systems.(including.hydropower).and.flood.control..For.example,.in.urban.environments,.more.heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and.water.and.wastewater.treatment.facilities;.sea.level.rise.could.lead.to.salinisation.of.water.supplies.from.coastal.aquifers..climate.change.could.increase.irrigation.demand.due.to.the.combination.of.decreased.rainfall.and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation.systems.that.are.in.many.cases.already.under.performing..changes.in.river.flows.have.a.direct.impact.on.hydropower.generation..soil.erosion.from.increased.rainfall.intensity.could.affect.watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation.of.multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the.infrastructural.and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even.national.boundaries.
The extent to which water investments are impacted by climate change will have ramifications that could extend to the economy and society at large..this.depends.highly.on.the.degree.of.vulnerability.of.the.system.(or.project).design.and.operation,.including.its.internal.capacity.to.adapt..For.example,.pressure.on.water.supply.and.sanitation.facilities.could.have.a.wide.range.of.adverse.effects.on.human.health..reduced.availability.of.water.for.irrigation.could.threaten.food.security,.rural.development,.environmental.uses.of.water,.and.the.economies.of.countries.that.are.largely.dependent.on.the.agricultural.sector..reduced.freshwater.supplies.may.lead.to.a.shift.towards.increased.use.and.dependence.on.groundwater..reduced.water.for.hydropower.generation.(or.increased.fluctuations.in.river.flows).could.decrease.electricity.grid.stability.and.reliability,.with.consequent.effects.on.the.economy.as.well.as.livelihoods.dependent.on.downstream.uses.of.water..managing.sedimentation.(e.g.,.through.flushing).could.affect.the.timing,.supply.and.quality.of.water.to.the.various.sectors.served.by.a.multi-purpose.infrastructures,.with.impacts.felt.in.the.larger.economy..in.the.worst.case,.competition.over.limited.water.resources.across.sectors.and.nations.could.worsen.hostility.and.mistrust,.and.increase.conflicts.over.water.and.further.degrade.freshwater.ecosystems.
value added and content of this report
The primary objective of this report is to support Bank operations and the client countries in making informed and climate-smart water investment decisions. this.report.provides.an.overview.of.a.package.of.background.technical.reports,.papers,.and.analyses.commissioned.by.the.bank’s.water.Anchor.in.an.attempt.to.understand.the.risks.of.the.impact.of.climate.change.on.the.bank’s.water.investments.and.to.provide.ways.to.manage.them..this.package.of.information,.knowledge,.and.guidelines.is.intended.for.use.by.the.bank.water.staff.and.client.countries.
4 Theterm‘system’incapturesallelements—frominfrastructuretoinstitutions—thatcontributetoperformanceoftheintendedfunction.Inthisreport,systemandinfrastructureissometimesusedinterchangeablywithwatersystemswiththeimpliedbroadestdefinitionoftheterm.
6
This report adds value to the Bank’s work on climate change and water in the following areas:
A compilation of the state-of-the-knowledge for the Bank’s water practice..there.is.a.wealth.of.information.on.climate.change,.adaptation.and.the.water.sector,.which.is.held.within.the.bank.and.beyond,.and.which.includes.both.analytical.studies.and.on-the-ground.experiences..the.body.of.knowledge.on.this.subject.is.rapidly.expanding..A.significant.added.value.of.this.report.is.in.bringing.together.the.various.information,.references,.and.conclusions.from.this.vast.knowledge.base.in.a.condensed,.structured.and.coherent.manner.specifically.useful.to.the.bank’s.water.practice..Another.value.of.this.report,.equally.important.to.the.water.professionals.is.provision.of.the.best.available.information.regarding.the.gaps.in.the.knowledge,.critical.assumptions.made.in.the.modeling.effort,.shortcomings.and.pitfalls.in.the.analysis,.and.potential.misuse.of.the.results.
A consolidated package of historical data and projections of key hydrologic drivers useful for policy, planning, and investment decisions in the sector..one.potential.difficulty.with.using.climate.information.in.impact.assessments—including.in.the.water.sector—is.the.‘mis-match’.between.the.low.spatial.(and.temporal).resolution.of.gcms,.on.the.one.hand,.and.the.scale.at.which.assessments.need.typically.to.be.conducted.for.investment.purposes,.on.the.other..to.facilitate.initial.dialogue.and.assessment.for.incorporation.of.climate.change.in.water.investments,.a.set.of.historical.and.projected.hydrologic.parameters.have.been.compiled.for.bank.use..the.historical.information.is.based.on.1960–1990.period.organized.to.serve.as.baseline..the.projections.are.based.on.projections.from.22.gcms,.scaled.to.basin.level.and.translated.to.hydrologic.drivers.and.indicators.for.planning.and.investment.decisions.
An analysis of the exposure of Bank water investments to current hydrologic variability and future climate change. the.world.bank’s.water.investments.are.exposed.to.current.hydrologic.variability.and.future.climate.change..the.historical.and.future.hydrologic.drivers.and.indicators.are.mapped.on.to.the.bank’s.active.and.pipeline.projects.to.assess.the.potential.exposure.to.hydrologic.variability.and.climate.change..Assessment.of.the.exposure.of.the.water.services.investments.(.e.g.,.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation).and.water.management.systems.(e.g.,.flood.control,.river.basin.management,.and.multi-purpose.infrastructure).are.reported.here.
Climate change implications on groundwater and groundwater management adaptation opportunities are highlighted. relative.to.surface.water,.aquifers.have.the.capacity.to.store.large.volumes.of.water.and.are.naturally.buffered.against.seasonal.changes.in.temperature.and.rainfall..they.provide.a.significant.opportunity.(through.conjunctive.use.and.management.of.surface.and.groundwater.resources,.managed.aquifer.recharge.and.land.use.protection.and.management).to.optimize.use.of.water.resources,.to.store.excess.water.during.high.rainfall.periods,.to.reduce.evaporative.losses.and.to.protect.water.quality..However,.these.opportunities.have.received.little.attention,.in.part.because.groundwater.is.often.poorly.understood.and.managed.
Freshwater ecosystem adaptation options..As.hydrology.and.water.use.changes.due.to.altered.precipitation.patterns.and.as.waters.become.warmer,.freshwater.ecosystems.will.be.stressed.further.and.the.aquatic.life.they.now.support.will.be.replaced.by.other.species.better.adapted.to.warmer.water.(i.e.,.cold.water.fish.will.be.replaced.with.warm.water.fish)..this.process,.however,.will.occur.at.an.uneven.pace.disrupting.ecosystem.health.and.allowing.non.indigenous.and/or.invasive.species.to.become.established..in.the.long.term,.warmer.water.and.changing.river.flows.may.
7
result.in.significant.deterioration.of.aquatic.ecosystem.health.in.some.areas.(usePA,.2008)..A.key.response.to.climate.adaptation.is.to.develop.both.adaptive.management.systems.that.can.enable.ecosystems.to.respond.to.changes.and.the.establishment.of.resilient.ecosystems.
Guidance on inclusion of risk-based decision making in water investments..world.bank.water.investments.can.have.significant.exposure.and.vulnerability.to.climate.change..most.water.investments.can.no.longer.be.designed.based.on.average.conditions.and.simplified,.deterministic.assumptions..to.avoid.or.reduce.climate-induced.losses,.a.shift.in.decision.making.from.traditional.deterministic.approach.to.a.risk-based.approach.is.necessary..this.will.help.to.better.understand.(and.characterize).the.risks.and.develop.ways.to.manage.them..A.framework.for.systematic.and.pragmatic.incorporation.of.risk.and.uncertainty.in.the.bank’s.water.investment.project.cycle.is.presented.in.this.report.
The content of this report will help enhance sustainability of Bank investments in the water sector by providing staff and client countries..the.report.presents/summarizes.approaches,.methodologies.and.guidelines.for.incorporating.hydrologic.variability,.climate.change,.and.risk.management.in.project,.program.and.sector-wide.investments..it.will.contribute.to.preparation.of.future.country.water.resources.assistance.strategies.that.incorporate.adaptation.to.climate.change.in.investment.planning.and.inform.institutional.and.policy.reform.for.sustainable.management.of.water.resources..the.report.begins.with.illustrating.the.impact.of.climate.change.on.the.hydrologic.cycles.and.identifies.the.drivers.significant.to.investments..the.scientific.effort.to.understand.and.describe.climate.change.is.assessed.for.application.to.the.bank.operations..the.impact.of.the.changing.hydrologic.cycle.on.water.availability,.demand,.and.management,.including.the.potential.vulnerability.of.various.water.systems.and.its.implication.in.the.sector.is.then.examined..A.package.of.climate.change.projections.at.a.scale.appropriate.for.planning.and.investment.decisions.had.been.developed..this.package.is.designed.to.serve.as.a.common.basis.for.analysis.of.the.impact.of.climate.change.in.any.sector..using.these.projections,.exposure.of.the.current.and.future.bank.portfolio.to.climate.change.is.evaluated..Finally,.an.agenda.for.continued.effort.in.the.water.practice.to.address.hydrologic.variability.and.climate.change.is.proposed.
The primary audience for this report and its associated technical reports is World Bank staff and as appropriate the client countries. the.objective.is.to.equip.bank.staff.with.needed.knowledge.and.tools.to.effectively.incorporate.climate.variability.and.change.in.their.operational.work.in.the.water.sector..the.outcome.of.this.work.will.also.assist.client.countries.in.making.informed.decisions.on.incorporating.hydrologic.variability.and.adaptation.strategies.into.long-term.planning.and.investment.decisions..this.is.timely.and.relevant.as.both.the.bank.staff.and.client.country.professionals.are.becoming.increasingly.aware.of.the.risks.of.no.action..A.comprehensive.dissemination.strategy,.including.capacity.building.programs,.for.bank.staff.and.clients.countries.will.be.developed.by.the.water.Anchor.and.implemented.in.collaboration.with.the.regions.and.as.part.of.the.world.bank.institute.climate.change.activities.
9
CHaPTer 2: imPaCT of ClimaTe CHange on THe HydrologiC CyCle and THe waTer resourCe base
The climate system and the hydrologic cycle are intimately linked
Powered by solar radiation, the climate system is a complex, inter-active system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things (IPCC, 2007a)..the.climate.system.evolves.over.time.under.the.influence.of.its.own.internal.dynamics.and.due.to.changes.in.external.factors.that.affect.climate.(called.‘forcings’)..external.forcings.include.natural.phenomena.(e.g.,.volcanic.eruptions.and.solar.variations),.as.well.as.anthropogenic.changes.that.alter.atmospheric.composition.and.land-use.change..changes.in.any.of.these.factors.can.alter.the.balance.between.incoming.(solar).short-wave.radiation.and.outgoing.long-wave.radiation..the.climate.system.responds.both.directly.and.indirectly.(through.feedback.mechanisms).to.such.changes..description.of.weather,.climate,.and.climate.variability.are.provided.in.box.2.1.
Any variability in climate affects the hydrologic cycle.5.the.hydrologic.cycle.describes.the.continuous.movement.of.water.through.the.oceans,.atmosphere,.and.land.surface.(Figure.2.1)..driven.by.solar.energy,.the.hydrologic.cycle.begins.with.the.evaporation.of.water.from.the.surface.of.the.ocean..As.moist.air.is.lifted,.it.cools.and.water.vapor.condenses.to.form.clouds..moisture.is.transported.around.the.globe.and.returns.to.the.surface.as.precipitation.(in.its.multiple.forms.of.rain.and.snow,.sleet,.hail,.etc.)..once.the.water.reaches.the.ground,.one.of.two.processes.may.occur:.i).water.evaporates.or.transpires.back.into.the.atmosphere6.or.ii).the.remaining.water.penetrates.the.surface.and.becomes.groundwater..groundwater.seeps.into.oceans,.rivers,.and.streams..the.balance.of.water.that.remains.on.the.earth’s.surface.is.runoff,.which.empties.into.lakes,.rivers.and.streams.and.is.carried.back.to.the.oceans,.where.the.cycle.begins.again.(bramer.et.al.,.2008).
Box 2.1 Weather, climate, and climate variability
Weather.is.a.measure.of.short-term.changes.in.atmospheric.conditions.(e.g.,.temperature,.precipitation.
amount,.humidity)..Climate.describes.the.typical.weather.of.a.region..more.precisely,.it.is.a.statistical.
description.of.long-term.(e.g.,.30.years).average,.variances,.and.extremes.derived.from.observed.weather..
Climate variability generally.refers.to.fluctuations.around.a.mean.climate.that.occur.on.seasonal,.inter-
annual,.and.even.decadal.timescales..A.significant.component.of.climate.variability.can.be.linked.to.a.relatively.
small.number.of.patterns.(or.modes).of.variability,.including.el.niño-southern.oscillation.(enso),.north.
Atlantic.oscillation.(nAo),.and.Atlantic.multi-decadal.oscillation.(Amo)..these.events—which.may.occur.
on.timescales.of.years.to.decades—lead.to.changes.in.atmospheric.circulation.and.rainfall.distribution.that.
characterize.many.parts.of.the.world..A.key.point.is.that.these.patterns.are.not.long-term.changes.in.climate,.
but.rather.deviations.from.mean.climate.conditions.
5 Theinfluencealsoworksinthereversedirection,i.e.,thechangesinthehydrologiccyclecanalsoaffecttheclimatesystem.Thefocushere,however,isontheimpactofclimaticchangeonhydrology.
6 Evaporationiswaterthatturnstowatervapordirectlyfromsurfacewaterbodies(e.g.,oceans,lakes,andreservoirs).Transpirationiswaterthatistakenupbyplantsandthenreleasedtotheatmosphere.
10
evidence is mounting that climate change is occurring and that it is altering the hydrologic cycle
Climate change is “an altered state of the climate that can be identified by changes in the mean and/or variability of its properties, and that persists for an extended period, typically decades or longer” (Bates, et al., 2008)..definitions.of.climate.change.vary,.not.in.terms.of.what.it.is,.but.in.terms.of.what.is.responsible,.and.specifically.whether.it.is.attributable.to.natural.causes.and/or.anthropogenic.causes..the.united.nations.Framework.convention.on.climate.change.(unFccc).definition.of.climate.change.is.restrictive,.in.the.sense.that.it.includes.only.anthropogenic-induced.changes.and.not.those.associated.with.natural.causes..the.intergovernmental.Panel.on.climate.change.(iPcc).definition,.which.includes.both,.is.more.widely.accepted,.so.it.is.adopted.here..According.to.the.iPcc.definition,.climate.change.can.be.attributed.to.natural.internal.processes.and.to.external.forcings,.both.natural.and.anthropogenic.
While there is wide agreement on the potential causes of climate change, it is difficult to attribute observed (or detected) changes in climate to a specific cause, and, in particular to anthropogenic changes..the.difficulties.of.distinguishing.between.human.and.natural.causes.of.climate.change.increase.at.finer.spatial.and.temporal.scales..nonetheless,.the.iPcc.has.found,.based.on.a.number.of.observed.trends,.that.global.climate.is.changing,.and.that.it.is.very likely.that.human.activities.are.in.part.responsible..the.earth’s.temperature.is.highly.variable,.with.year.to.year.changes.often.masking.the.overall.rise.of.approximately.0.74°c.that.has.occurred.from.1906–2005.(iPcc,.2007a;.bates,.et.al.,.2008)..nevertheless,.there.is.a.clear.twentieth.century.upward.trend,.and.in.particular.a.rapid.rise.over.the.past.50.years..greenhouse.gases.that.trap.
Figure 2.1 The Hydrologic Cycle
Source: iPcc.2007c,.pg..96,.FAQ1.2,.Fig..1.
11
heat.(water.vapor,.carbon.dioxide,.and.methane).exist.naturally.in.the.atmosphere..However,.there.is.increasingly.strong.evidence.that.anthropogenic.radiative.forcings—and.in.particular.those.deriving.from.increased.concentrations.of.co2.from.burning.of.fossil.fuels—have.contributed.to.global.warming.
There is now strong evidence that global warming is changing hydrologic cycle..long-term.trends.in.hydrologic.variables.are.difficult.to.detect.due.to.significant.natural.variability.in.all.components.of.the.hydrologic.cycle.over.both.time.and.space..However,.observed.changes.in.the.hydrologic.cycle.at.the.sub-continental.scale.have.consistently.been.associated.with.climate.warming.over.the.past.several.decades.7.A.summary.of.the.evidence,.based.on.iPcc.findings.is.provided.below.(bates,.et.al.,.2008;.kundzewicz,.et.al.,.2007).
Precipitation (including extreme events) and water vapor:
•.the.average.atmospheric.water vapor content.has.increased.since.at.least.the.1980s.over.land.and.ocean.as.well.as.in.the.upper.troposphere.
•.over.the.20th.century, mean precipitation.has.mostly.increased.over.land.in.high.northern.latitudes.over.the.period.1901.to.2005,.while.decreases.have.dominated.from.10°s.to.30°n.since.the.1970s.
•.widespread.increases.in.heavy precipitation events.(e.g.,.above.the.95th.percentile).have.been.observed,.particularly.in.mid-latitude.regions.and.even.where.total.precipitation.has.decreased.
•.globally,.soil moisture.has.decreased..Droughts.have.become.more.intense.and.longer,.especially.in.the.tropics.and.subtropics.
•.there.is.observational.evidence.that.intense.tropical cyclone.activity.has.increased.is.some.regions.(e.g.,.north.Atlantic.since.about.1970)..there.is.no.clear.trend.in.the.frequency.of.tropical.cyclones.
Snow and land ice:
•.Snow cover.has.decreased.in.most.regions,.especially.in.spring.and.summer;.degradation.of.permafrost and seasonally frozen ground.has.occurred.in.many.areas;.freeze-up.and.break-up.dates.for.river and lake ice.have.been.delayed.and.taken.place.earlier,.respectively,.in.the.northern.hemisphere,.where.data.are.available.
•.considerable.mass.loss.has.occurred.on.the.majority.of.glaciers and ice caps.worldwide.(box.2.2).
future changes in climate are projected to lead to a further acceleration and intensification of the hydrologic cycle
Changes in the global climate system during the 21st century will very likely be larger than those observed during the 20th century. the.iPcc.has.projected.that.by.the.end.of.the.21st.century,.the.earth’s.average.annual.mean.temperature.is.likely.to.rise.by.between.1.1.and.6.4°c.from.the.mean.in.1990..the.wide.range.in.projections.of.mean.surface.air.warming.result.from.two.factors:.the.sres.(special.report.on.emissions.scenarios).emissions.scenario.and.different.models.used. However,.the.iPcc.concluded.that.it.is.very likely.that.nearly.all.land.areas.will.warm.more.rapidly.than.the.global.average.and.particularly.those.at.northern.high.latitudes.in.the.cold.
7 Thereareseveralprocessesthroughwhichchangesinhydrologicalvariablescanproducefeedbackeffectsonclimate(e.g.,landsurfaceeffects,feedbacksthroughchangesinoceancirculation,emissionsorsinksaffectedbyhydrologicalprocesses),butthefocushereisinthereversedirection,thatis,theimpactofclimatechangeonhydrology.
12
season..climate.variability.is.also.likely.to.change,.although.the.nature.of.this.change.is.uncertain..Along.with.the.substantial.changes.in.average.climatic.conditions,.it.is.likely.that.there.will.also.be.changes.in.the.seasonal.cycle.of.the.climate.and.in.the.intensity.and.frequency.of.extreme.events.(refer.below).
It is projected that many of the currently observed changes in the hydrologic cycle will become more pronounced with continuing climate change..Projected.increases.in.global.temperatures.are.associated.with.changes.in.the.hydrologic.cycle,.including.increasing.atmospheric.water.vapor,.changes.in.precipitation.patterns.(frequency.and.intensity),.leading.to.changes.in.soil.moisture..these.changes.are.often.referred.to.as.an.intensification and acceleration of the hydrologic cycle..the.result.of.hydrologic.change.and.increased.variability.is.shorter.periods.of.more.intense.rainfall,.and.longer.warmer.dryer.periods..iPcc.findings.on.the.projected.impacts.of.climate.change.on.the.hydrologic.cycle.are.summarized.below.(bates,.et.al.,.2008;.kundzewicz,.et.al.,.2007).
•.Annual average precipitation:.Precipitation.is.projected.to.increase.in.high.latitudes.(very.likely).and.parts.of.the.tropics,.and.decrease.in.some.subtropical.and.lower.mid-latitude.regions.(likely).
•.Precipitation Extremes:.increased.precipitation.intensity.and.variability.is.projected.to.increase.the.risk.of.flooding.and.drought.in.many.areas.(increased.rain-generated.floods.very.likely,.increased.extreme.drought.likely)..it.is.likely.that.future.tropical.cyclones.will.become.more.intense,.with.larger.peak.wind.speeds.and.heavier.precipitation.
•.Glaciers and snow:.water.stored.in.glaciers.and.snow.cover.is.projected.to.decline.(high.confidence).
•.Sea level:.in.all.but.one.sres.marker.scenario.(b1),.the.average.level.of.sea.level.rise.during.the.21st.century.will.very.likely.exceed.the.1961–2003.average.rates..thermal.expansion.is.the.
Box 2.2 Mass loss of glaciers
tropical.glaciers.located.between.bolivia.and.venezuela.decreased.in.area.by.just.under.20%.between1970.
and.2002..several.glaciers.in.south.America,.such.as.ecuador’s.cotacachi,.have.already.disappeared.(eos,.
19.june.2007)..Peruvian.glaciers.declined.nearly.22.percent.between.1970.and.1997.as.a.result.of.warmer.
temperatures..major.additional.reductions.in.surface.area.have.been.measures.since.then..the.largest.of.these.
glaciers.in.the.cordillera.blanca.have.lost.15.percent.of.their.glacier.surface.area.in.a.period.of.30.years..
many.of.the.smaller.glaciers.in.Peru.have.already.been.heavily.affected.and.others.are.likely.to.completely.
disappear.within.a.generation.
evidence.suggests.that.the.rate.of.temperature.increase.in.nepal.and.the.tibetan.Plateau.is.greater.than.the.
global.average,.and.a.pronounced.warming.in.winter.has.already.been.observed..retreating.glaciers.in.the.
Himalayas.present.one.of.the.most.difficult.challenges.for.the.region,.because.glaciers.and.snow.provide.water.
storage.that.helps.to.regulate.the.flow.of.perennial.rivers.and.to.enhance.low.season.flows..the.Himalayan.
glaciers.are.reducing.at.a.rate.of.10–15.m.every.year.(tehelka,.3.may.2008)..the.region.is.also.at.risk.of.an.
increase.in.the.frequency.and.magnitude.of.climate.change-related.natural.disasters,.including.glacier.and.
snow.melt,.and.glacial.lake.outburst.floods.
observed.and.anticipated.climate.change-related.impacts.include.deterioration.of.watersheds.and.depletion.of.
water.recharge.capacities,.increased.likelihood.of.mountain.fires,.and.biotic.changes.in.ecosystem.thresholds.
and.their.ability.to.store.water..the.effects.and.consequences.may.be.different.at.the.initial.and.final.stages.of.
the.glacier.retreat.and.may.differ.depending.on.location.
13
largest.component..it.has.been.suggested.that.melting.of.glaciers,.ice.caps.and.the.greenland.ice.sheet.can.contribute.to.sea.level.rise.as.a.result.of.shift.in.the.gravitational.pull.created.by.significant.loss.of.mass.at.the.poles.
•.Evapotranspiration:.changes.in.temperature,.radiation,.atmospheric.humidity.and.wind.speed.affect.potential.evapotranspiration.(or.evaporative.demand)..in.addition,.increasing.atmospheric.co2.concentration.directly.alters.plant.physiology,.thus.affecting.evapotranspiration..Potential.evaporation.is.projected.to.increase.almost.everywhere..transpiration.may.increase.or.decrease.
•.Soil moisture:.Annual.mean.soil.moisture.content.is.projected.to.decrease.in.the.sub-tropics.and.the.mediterranean.region,.and.at.high.latitudes.where.snow.cover.diminishes..soil.moisture.is.projected.to.increase.in.east.Africa,.central.Asia.and.other.regions.with.increased.precipitation.
table.2.1.summarizes.the.observed.trends.and.projections.for.the.21st.century.of.key.hydrologic.variables.
Table 2.1 Changes in Key Hydrologic Variable
Key Variables Observed Trends Projections for 21st Century
Total Precipitation trend.is.unclear..general.increases.in.
precipitation.over.land.from.30on.to.85on..
notable.decreases.from.10os.to.30on.
increase.(about.2%/oc).in.total.
precipitation..High.latitude.areas.generally.
projected.to.increase..many.low.to.mid-
latitude.areas.projected.to.decrease..
changes.at.the.regional.scale.vary.
Atmospheric
Water Vapor
Content
increasing.in.lower.atmosphere.(lower.
troposphere;.about.1%/decade).in.specific.
humidity;.little.change.in.relative.humidity
increasing
Intensity of
Precipitation
disproportionate.increase.in.volume.of.
precipitation.in.heavy.or.extreme.precipitation.
events
increasing.(about.7%/oc)
Droughts drought,.as.measured.by.the.Palmer.drought.
severity.index,.increased.in.the.20th.century,.
although.some.areas.became.wetter
increasing.in.many.areas,.particularly.
lower.latitudes..decreasing.in.many.high.
latitude.areas..Patterns.are.complex.
Tropical Cyclones increases.in.intensity,.particularly.in.north.
Pacific,.indian.ocean,.and.southwest.Pacific
increase.in.intensity..changes.in.frequency.
and.track.are.uncertain
Glaciers and
snow cover
decrease.in.mass.of.glaciers,.but.not.in.all.
regions..decrease.in.snow.cover.in.regions.in.
the.northern.Hemisphere..earlier.peak.runoff.
from.glacier.and.snowmelt.
continued.decrease.in.glacial.mass.and.
snow.cover
Sea level increased.about.0.2.meters.over.the.20th.
century..A.rise.equivalent.to.0.3.meters.per.
century.was.recorded.since.the.early.1990s,.
but.it.is.not.clear.if.this.is.an.acceleration.of.
long.term.sea.level.rise
iPcc.projects.0.2.to.0.6.meters.by.2100,.
but.upper.end.could.be.much.higher.
Source: derived.from.iPcc,.2007a;.kevin.trenberth,.national.center.for.Atmospheric.research..Personal.communication..may.19,.2008;.trenberth.et.al.,.2003.
14
Hydrologic change and increased variability will have a significant impact on the water resource base
Changes in the hydrologic cycle will have both direct and indirect effects on the magnitude and timing of runoff, groundwater recharge, water quality, and the frequency and intensity of extreme events (droughts and floods). Projected.impacts.on.each.on.these.components.of.the.water.resource.base—summarized.from.various.iPcc.reports—are.provided.below.
Uncertainties in projected climate change impacts
There are significant uncertainties in projections of the impact of climate change on the water resource base. these.uncertainties.derive.from.a.number.of.sources,.including.from.internal.variability.of.the.climate.system,.uncertainty.in.future.emissions,.the.translation.of.these.emissions.into.climate.change.by.global.climate.models,.and.model.uncertainty.(bates,.et.al.,.2008)..uncertainties.in.projections.increase.with.the.length.of.the.time.horizon,.and.temperature.is.projected.with.more.certainty.than.precipitation..where.hydrological.models.are.used.to.project.changes.on.water.resources,.uncertainties.arise.from.the.mismatch.between.their.respective.spatial.and.temporal.scales..downscaling.methods.have.been.used.to.address.the.scale.issues,.but.they.introduce.additional.uncertainties..the.greatest.uncertainties.in.the.effects.of.climate.on.river.discharge/runoff.arise.from.climate.change.scenarios,.as.long.as.a.conceptually.sound.hydrological.model.is.used..Additional.uncertainty.is.introduced.in.estimating.impacts.on.groundwater.recharge,.water.quality,.or.flooding/drought.as.translation.of.climate.into.response.is.less.well.understood.(Arnell,.2004)..uncertainties.in.climate.change.impacts.on.the.hydrologic.cycle.and.water.resource.base.are.discussed.in.more.detail.later.in.this.report.(also.refer.box.2.3).
Runoff and river discharge
The most dominant climatic drivers for runoff and river discharge are precipitation, temperature and evaporative demand (IPCC, 2007a)..changes.in.the.volume,.timing.and.
Box 2.3 Primary sources of uncertainty in projections of hydro-climatic change
uncertainties.in.projected.changes.in.the.hydrological.systems.due.to.climate.change.arise.from.a.number.of.
sources..these.include.the.uncertainties.in.the.internal.variability.of.the.climate.system;.uncertainty.in.future.
greenhouse.gas.and.aerosol.emissions.(and,.importantly,.the.populations,.levels.of.economic.development,.
and.technologies.that.generate.them);.the.translation.of.these.emissions.into.climate.change.by.global.climate.
models;.and.model.uncertainty..Further.uncertainties.in.hydrological.projections.arise.from.the.structure.of.
current.climate.models..current.models.generally.exclude.some.feedbacks.from.vegetation.to.climate.change..
most.simulations.used.for.deriving.climate.change.projections.also.exclude.anthropogenic.changes.in.land.
cover.
incorporating.climate.model.results.in.freshwater.studies.also.adds.uncertainties,.which.are.associated.with.the.
different.spatial.scales.of.climate.models.and.hydrologic.models.and.biases.in.long-term.mean.precipitation.
as.computed.by.global.climate.models.for.the.current.climate..methods.that.have.been.used.to.address.the.
scale.differences.–.including.dynamical.or.statistical.downscaling.methods.–.introduce.uncertainties.into.the.
projection..methods.to.address.biases.in.simulated.mean.precipitation.do.not.take.into.account.inter-annual.
or.day-to-day.variability.in.climate.parameters.and,.therefore,.risk.underestimating.future.floods.and.droughts..
(bates,.et.al,.2008).
15
intensity.of.precipitation,.and.whether.precipitation.falls.as.snow.or.rain,.have.an.impact.on.river.flows..temperature.is.particularly.important.in.snow-dominated.basins.and.in.coastal.areas.(due.to.the.impact.of.temperature.on.sea.level.rise)..changes.in.potential.evapotranspiration.can.offset.small.increases.in.precipitation.and.aggravate.further.the.effect.of.decreased.precipitation.on.surface.waters..different.catchments.respond.differently.to.the.same.changes.in.climatic.drivers,.depending.largely.on.catchment.physiogeographical.and.hydrogeological.characteristics.and.the.amount.of.lake.or.groundwater.storage.in.the.catchment.(kundzewicz,.et.al.,.2007).
At the global scale, there is evidence of a broadly coherent pattern of change in annual runoff,.with.some.regions.experiencing.an.increase,.particularly.at.higher.latitudes,.and.others.a.decrease,.for.example,.parts.of.west.Africa,.southern.europe.and.southern.latin.America.(bates,.et.al.,.2007)..However,.attribution.to.long-term.climate.change.is.difficult.because.of.natural.variability.and.the.potential.influence.of.non-climatic.factors,.such.as.land.use.changes..there.is.more.robust.and.widespread.evidence.that.the.timing of river flows.in.many.regions.where.winter.precipitation.falls.as.snow.has.been.significantly.altered.due.to.rising.temperatures..world.bank.(2009).indicate.that.climate.change.is.expected.to.alter.the.surface.hydrology.of.Peru.as.a.result.of.changes.in.hydrology.and.runoff.from.the.Andean.lakes.and.mountain.wetlands—a.major.source.of.water.for.hydropower,.urban.water.supply.systems.and.agriculture—have.been.impacted.by.climate.change.
Several hundred studies of the potential effects of climate change on river flows have been undertaken,.but.many.of.these.are.regional.and.heavily.focused.towards.europe,.north.America,.and.Australasia..of.the.global.scale.assessments,.milly,.et.al.,.2005.is.one.of.the.most.frequently.cited..Figure.2.2.shows.the.mean.runoff.change.until.2050.for.the.sres.A1b.scenario.from.an.ensemble.of.twenty-four.climate.model.runs.(from.twelve.different.gcms)..As.shown.in.the.figure,.total.annual.river.runoff.globally.is.projected.to.increase,.although.there.is.considerable.variability.across.regions.with.significant.decrease.in.mid-latitudes.and.some.parts.of.the.dry.tropics.and.significant.increase.in.high.latitudes.and.wet.tropics.
Patterns depend primarily on changes in the volume and timing of precipitation, and whether precipitation falls as snow or rain..in.areas.where precipitation currently falls as snow,.a.very.robust.finding,.consistent.across.a.number.of.studies,.is.that.warming.would.lead.to.changes.in.the.seasonality.of.river.flows..in.areas fed by glaciers,.higher.temperatures.would.lead.to.increased.river.run-off.and.discharge.peaks.in.the.short.term,.but.the.contribution.of.glacier.melt.would.gradually.diminish.over.the.next.few.decades..in.areas with little or no snowfall,.changes.in.runoff.are.much.more.dependent.on.changes.in.rainfall.than.in.temperature..A.general.conclusion.of.studies.is.that.flow.seasonality.would.increase,.with.higher.flows.in.the.peak.flow.season.and.either.lower.flows.during.the.low.flow.season.or.extended.dry.periods.(kundzewicz,.et.al.,.2007).
Groundwater
Groundwater and soil moisture collectively account for over 98% of the available global freshwater resources. groundwater.levels.correlate.more.strongly.with.precipitation.than.with.temperature,.but.temperature.becomes.more.important.for.shallow.aquifers.and.in.warm.periods.(kundzewicz,.et.al.,.2007).
In contrast to surface water systems, climate-related changes in groundwater levels have neither been well studied nor adequately observed..this.is.due.to.the.neglect.of.groundwater.
16
management.in.general.as.well.as.due.to.the.hidden.nature.of.groundwater,.the.very.slow.reaction.of.groundwater.systems.to.changing.conditions,.and.measurement.difficulties..there.is.an.observed.decreasing.trend.in.groundwater.levels.during.the.last.few.decades,.but.this.has.been.attributed.to.over-extraction.(groundwater.pumping.exceeding.recharge.rates).
Critical threats to groundwater as a result of climate change include:•.reduced.groundwater.recharge—as.the.result.of.reductions.in.precipitation,.changes.in.its.
seasonal.distribution.and/or.changes.in.the.distribution.of.precipitation.between.rainfall.and.snow..the.magnitude.of.change.in.groundwater.recharge.will.vary,.dependent.on.local.conditions..in.some.areas,.rainfall.may.fall.below.the.threshold.required.for.any.recharge.to.occur;
•.a.rapid.shift.towards.increased.utilization.of.groundwater.as.surface.waters.become.less.reliable.in.selected.parts.of.the.world;
•.contamination.of.coastal.aquifers.and.contraction.of.freshwater.lenses.on.small.islands—due.to.salt.water.intrusion.as.sea.level.rises,.coupled.with.contamination.by.more.extensive.storm.surge.incursions..salinisation.of.shallow.aquifers.could.also.result.from.increased.evapotranspiration,.particularly.in.semi-arid.and.arid.regions.
Figure 2.2 Large-scale relative changes in annual runoff (water availability, in percent) for the period 2090–2099, relative to 1980–1999
values.represent.the.median.of.12.climate.models.using.the.sres.A1b.scenario..white.areas.are.where.less.than.66%.of.the.12.models.agree.on.the.sign.of.change.and.hatched.areas.are.where.more.than.90%.of.models.agree.on.the.sign.of.change..the.quality.of.the.simulation.of.the.observed.large-scale.20th.century.runoff.is.used.as.a.basis.for.selecting.the.12.models.from.the.multi-model.ensemble..the.global.map.of.annual.runoff.illustrates.a.large.scale.and.is.not.intended.to.refer.to.smaller.temporal.and.spatial.scales..in.areas.where.rainfall.and.runoff.is.very.low.(e.g..desert.areas),.small.changes.in.runoff.can.lead.to.large.percentage.changes..in.some.regions,.the.sign.of.projected.changes.in.runoff.differs.from.recently.observed.trends..in.some.areas.with.projected.increases.in.runoff,.different.seasonal.effects.are.expected,.such.as.increased.wet.season.runoff.and.decreased.dry.season.runoff..studies.using.results.from.few.climate.models.can.be.considerably.different.from.the.results.presented.here..source:.milly,.et.al.,.2005;.iPcc,.2007b,.page.49,.Fig..3.5.
17
Relative to surface water supplies, there have been very few studies on the future impacts of climate change on groundwater or on groundwater/surface water interactions..According.to.the.results.of.a.global.hydrological.model,.groundwater.recharge,.when.averaged.globally,.increases.less.than.total.runoff.(doll.and.Florke,.2005)..while.the.distribution.of.impact.is.uneven,.the.projections.suggest.that.by.2050.there.may.be.significantly.less.recharge.(up.to.70%.less).in.north-eastern.brazil,.western.southern.Africa.and.along.the.southern.rim.of.the.mediterranean.sea.(see.Figure.2.3)..recharge.may.increase.in.some.areas.where.rainfall.is.projected.to.increase.substantially..in.some.locations.where.groundwater.resources.are.already.stressed,.this.may.help.to.relieve.pressures.on.groundwater.and.surface.water.resources..However,.in.areas.where.water.tables.are.already.high,.increased.recharge.might.lead.to.problems.of.soil.salinisation.and.waterlogging..the.very.few.studies.of.the.impacts.of.climate.change.on.individual.aquifers.show.very.site.specific.results.
Water quality
There is relatively little information on water quality, although a climate-related warming of lakes and rivers has been observed over recent decades. this.has.led.to.changes.in.
Figure 2.3 Global estimates of climate change impact on groundwater recharge
impact.of.climate.change.on.long-term.average.annual.diffuse.groundwater.recharge..Percent.changes.of.30-year.averages.groundwater.recharge.between.1961–1990.and.the.2050s.(2041–2070),.as.computed.by.wgHm.applying.four.different.climate.change.scenarios.(climate.scenarios.computed.by.the.climate.models.ecHAm4.and.Hadcm3,.each.interpreting.the.two.iPcc.greenhouse.gas.emissions.scenarios.A2.and.b2)..source:.döll.(2009),.Figure.1,.page.6.
18
species.composition,.organism.abundance.and.productivity,.and.phonological.shifts.in.some.freshwater.ecosystems..Higher.water.temperatures.have.been.reported.in.lakes.in.response.to.warmer.conditions,.prolonging.stratification.and.depleting.oxygen.in.deeper.layers..consistent.climate-related.trends.in.other.water.quality.parameters.(e.g.,.salinity,.pathogens,.or.nutrients).in.lakes,.rivers.or.groundwater.have.not.been.observed..likewise,.there.is.no.evidence.of.climate-related.changes.in.erosion.and.sediment.transport.(bates,.et.al.,.2008).
According to IPCC and based on a number of studies, higher water temperatures and changes in extremes, including floods and droughts, are projected to affect water quality and exacerbate many forms of water pollution.(iPcc.rating:.high.confidence). more.specifically,.the.following.potential.effects.have.been.noted:•.increased.water.temperatures.would.impact.oxygen.solubility,.stratification,.mixing,.and.other.
biochemical.processes.in.lakes.and.reservoirs,.as.well.as.the.assimilative.capacities.of.rivers.to.breakdown.organic.wastes.
•.increased.precipitation.intensity.would,.on.the.one.hand,.increase.dilution,.but.would,.on.the.other,.potentially.increase.sediment.loads.(via.increased.erosion),.nutrients,.pathogens.and.toxins.transported.to.downstream.water.bodies.
•.longer.periods.of.low.flows.would.reduce.the.dilution.capacity,.reduced.dissolved.oxygen,.increase.algal.blooms,.and.magnify.the.impact.of.water.pollution,.effecting.human.health,.ecosystems,.and.water.supplies.
•.reduced.lake.levels.may.lead.to.re-suspension.of.bottom.sediments.and.nutrient.cycling.•.sea.level.rise.could.increase.saltwater.intrusion.in.estuaries.and.coastal.aquifers,.and.may.also.
interfere.with.storm.water.drainage.and.sewage.disposal.
Floods and droughts
There are a number of climatic and non-climatic drivers influencing flood and drought impacts, and the terms ‘flood’ and ‘drought’ capture a wide array of meanings reflecting these different influences..Floods.include.river.floods,.flash.floods,.urban.floods,.sewer.floods,.glacial.lake.outburst.floods,.and.coastal.floods.(bates,.et.al.,.2008)..‘drought’.may.refer.to.meteorological.drought.(precipitation.well.below.average),.hydrological.drought.(low.river.flows.and.water.levels.in.rivers,.lakes.and.groundwater),.agricultural.drought.(low.soil.moisture).and.environmental.drought.(a.combination.of.the.above).(kundzewicz,.et.al.,.2007).
Although floods depend on a number of non-climatic factors (including, for example, existence of dams or dykes), there are indications that climate change might already have had an impact on their intensity and frequency..globally,.the.number.of.great.inland.flood.catastrophes.during.from.1996–2005.is.twice.as.large,.per.decade,.as.between.1950.and.1980.(bates,.et.al..2008)..this.has.been.associated.with.an.increasing.frequency.of.heavy.precipitation.events;.no.ubiquitous.increase.is.visible.in.trends.in.high.river.flows.8
Since the 1970s, droughts have also become more common, especially in the tropics and sub-tropics..iPcc.concluded.that.it.is.likely.that.the.area.affected.by.drought.has.increased.since.the.1970s,.and.it.is.more likely than not.that.there.is.a.human.contribution.to.this.trend..that.more.regions.are.experiencing.drought—as.measured.by.the.Palmer.drought.severity.index—is.associated.with.decreased.precipitation.and.increased.temperature,.which.increase.evapotranspiration.and.reduce.soil.moisture.
8Milly,etal.(2005)foundanincreaseinthefrequencyof‘large’floods(returnperiodgreaterthan100years)acrosstheglobefromananalysisofdatafromlargeriverbasins,butotherstudieshavenotfoundasimilartrend.
19
As discussed above, the frequency of heavy precipitation events is projected to increase over most regions throughout the 21st century, which could have a direct impact on flood events..milly,.et.al..(2005).found.that.for.fifteen.out.of.sixteen.large.basins.worldwide,.the.control.100-year.peak.volumes.of.monthly.river.flow.are.likely.to.be.exceeded.more.frequently.for.a.quadrupling.of.co2.levels..in.some.areas,.what.is.given.as.a.100.year.flood.now.(in.the.control.run).is.projected.to.occur.more.frequently,.even.every.2.to.5.years.(bates,.et.al.,.2008;.kundzewicz,.et.al.,.2007)..based.on.climate.models,.the.area.flooded.by.bangladesh.is.projected.to.increase.by.at.least.23–29%.with.a.global.temperature.rise.of.2.degrees.(bates,.et.al,.p..52).
According to IPCC, it is likely that the area affected by drought will increase (Bates, et al.,2008)..one.study.found.that.the.proportion.of.the.land.surface.experiencing.extreme.drought.at.any.one.time,.the.frequency.of.drought.events,.and.the.mean.drought.duration.were.projected.to.increase.by.the.2090s.by.10-.to.30-fold,.two-fold,.and.six-fold,.respectively.(bates,.et.al.,.2008)..in.the.low-flow.season,.droughts.in.snow-melt.fed.basins.may.increase.due.to.earlier.and.less.abundant.snowmelt..increased.drought.is.also.projected.for.regions.heavily.dependent.on.glacial-melt.water.for.their.main.dry-season.water.supply.
Freshwater ecosystems
the.responses.by.freshwater.ecosystems.to.a.changing.climate.can.be.described.in.terms.of.three.interrelated.components:.water.quality,.water.quantity.or.volume,.and.water.timing..A.change.in.one.often.leads.to.shifts.in.the.others.as.well.
Water quality.refers.to.how.appropriate.a.particular.ecosystem’s.water.is.for.some.“use,”.whether.biological.or.economic..many.fish.species,.for.instance,.have.narrow.habitat.quality.preferences.for.dissolved.oxygen,.water.temperature,.dissolved.sediment,.and.pH..Humans.generally.avoid.freshwater.for.drinking.or.cooking.if.it.has.excessive.levels.of.dissolved.minerals.or.has.a.very.high.or.low.pH..The changes in water quality (noted above) will contribute to changes in ecosystem composition, function and services, altering the resiliency of ecosystems..Higher.water.temperatures.in.lakes.will.impact.lake.productivity.and.distribution.of.fish.and.flora,.and.exacerbate.algal.blooms,.and.may.lead.to.odor.and.taste.problems.in.drinking.water..droughts.will.worsen.incidence.of.diarrheal.and.other.water-related.diseases,.especially.in.developing.countries.(wwF,.2009).
Water quantity.refers.to.the.water.volume.of.a.given.ecosystem,.which.is.controlled.through.the.balance.of.inflows.(precipitation,.runoff,.groundwater.seepage).and.outflows.(water.abstractions,.evapotranspiration,.natural.outflows)..At.a.global.scale,.precipitation.is.tending.to.fall.in.fewer.but.more.intense.events,.resulting.in.generally.more.precipitation..At.local.scales,.there.is.wide.variation..the.most.striking.changes.in.water.quantity.often.occur.with.precipitation.extremes.like.floods.and.droughts;.lake.and.wetland.levels.can.also.change.radically.as.a.result.of.even.slight.changes.in.the.balance.between.precipitation.and.evaporation..the.occurrence.of.precipitation.extremes.is.expected.to.increase.globally,.as.well.as.the.severity.of.extreme.events.themselves.(wwF,.2009).
Water timing or seasonality of flows.is.the.expected or.average.variation.in.water.quantity.over.some.period.of.time,.usually.reported.as.a.single.year.in.a.hydrograph..many.terrestrial.and.most.aquatic.species.are.extremely.sensitive.to.water.timing..natural.selection.has.adapted.(in.an.evolutionary.sense).the.behavior,.physiology.and.developmental.processes.of.many.aquatic.organisms.to.particular.water.timing.regimes,.such.as.spawning.during.spring.floods.or.
20
accelerated.metamorphosis.from.tadpole.to.adult.frog.in.a.rapidly.drying.wetland..shifts.in.water.timing.mean.that.there.may.be.detrimental.mismatches.between.behavior.and.the.aquatic.habitat..in.turn,.these.shifts.can.affect.fisheries.stocks.and.industries.that.depend.on.seasonal.water.flows.(wwF,.2009).
21
CHaPTer 3: imPaCT of ClimaTe CHange on waTer availabiliTy and use
Climate change could profoundly alter future patterns of both water availability and use, thereby increasing levels of water stress and insecurity, both at the global scale and in sectors that depend on water. indeed,.there.is.already.evidence.that.the.impacts.of.hydrologic.change.and.increased.variability.are.already.being.felt.and.that.even.small.changes.(e.g.,.in.the.magnitude.of.extreme.events).can.have.exponential.losses.(see.chapter.4)..this.said,.it.should.be.emphasized.that.climate.change.is.just.one.of.many.factors.determining.future.patterns.of.water.availability.and.use.
Climate change is expected to increase global water stress and insecurity
Climate change has the potential to increase existing levels of global water stress and insecurity—in terms of both surface and groundwater supplies—and to negatively impact water dependent sectors,.from.health.to.agriculture,.transport.to.industry,.and.energy.to.ecosystems..indeed, the IPCC concluded with high confidence that, globally, the negative impacts of future climate change on freshwater systems are expected to outweigh the benefits. more.specifically,.the.negative.effects.of.increased.precipitation.variability.and.seasonal.runoff.shifts,.water.quality.and.flood.risks.are.projected.to.outweigh.benefits.from.increased.annual.runoff.overall. it.is.important.to.emphasize,.however,.that.projections.of.water.stress.are based.on.certain.assumptions.about.future.driving.forces—both.climatic.and.non-climatic—as.well.as.water.resource.management.and.delivery.systems..many.assume—in.line.with.the.iPcc’s.projections—increasing.water.use,.primarily.as.a.result.of.population.and.income.growth,.but.also.partly.due.to.climate.change.in.the.case.of.irrigation..Additionally,.they.largely.take.as.given.current.water.systems,.including.infrastructure,.institutions.and.technology,.which.will.in.actuality.have.a.major.influence.on.water.availability.and.use.patterns.
Surface water stress assessments
The potential climate-induced changes in hydrology may aggravate global ‘water stress.’.most.studies.have.found.that.levels.of.water.stress.will.increase.as.a.result.of.climate.change,.although.the.influences.of.other.factors—demographic,.socio-economic,.and.technological.changes—are.even.more.significant,.particularly.in.shorter.time.horizons.(impacts.beyond.the.2050s.are.highly.dependent.on.the.population.projections.of.the.emissions.scenario.used)..there.are.large.differences.in.estimates.across.studies,.depending.not.only.on.how.climate.change.impacts.are.modeled,.but.also.on.which.other.drivers.are.included.in.the.assessment..Arnell.(2004)—who.accounts.for.population.growth.and.the.impact.of.climate.change—found.that.the.number.of.people.projected.to.experience.an.increase.in.water.stress.is.between.0.4.to.1.7.billion.in.the.2020s.and.between.1.and.2.7.billion.in.the.2050s.(using.the.A2.population.scenario.for.the.2050s).9
In terms of global water availability per capita, climate change would appear to reduce water stress, as projected increases in runoff are concentrated in the most populous parts of the world (mainly East and South-East Asia)..Further,.in.the.2050s,.differences.in.population.projections.were.found.to.have.a.larger.impact.on.the.number.of.people.living.in.water.stressed.basins.than.climate.change,.per se (kundzewicz,.et.al.,.2007)..
9Wherewaterstressisdefinedasbasinswithpercapitawaterwithdrawalsoflessthan1000m3/year.
22
Alcamo,.et.al..(2002).assessed.water.stress.as.a.function.of.population.growth.and.climate.change,.in.addition.to.changes.in.water.use.and.other.non-climatic.drivers.(income,.water.use.efficiency,.water.productivity,.industrial.production)..water.stress.was.found.to.increase.on.62–76%.of.the.land.area.and.to.decrease.on.20–29%.by.the.2050s.10.increased.water.availability.due.to.increased.precipitation.is.the.main.cause.for.decreasing.water.stress;.growing.water.withdrawals.(stimulated.more.by.income.growth.than.by.population.growth).is.the.main.cause.of.increasing.water.stress..when.environmental.flow.needs.are.incorporated—that.is,.the.amount.of.water.required.to.sustain.a.functioning.ecosystem—the.degree.of.water.stress.is.projected.by.some.to.increase.further.(smakhtin.et.al,.2003)..there.is.substantial.agreement.across.these.and.other.global.and.national-scale.assessments.that.semi-arid.and.arid.basins.are.the.most.likely.to.experience.water.stress..if.precipitation.decreases,.irrigation.water.use—which.dominates.in.most.semi-arid.river.basins—would.increase,.placing.additional.pressure.on.other.uses.
Groundwater stress assessments
Use of groundwater varies with the quality and availability of the resource, as well as with access to and the reliability of surface water..in.developing.and.developed.countries.alike,.it.contributes.to.human.health.and.socio-economic.development.through.the.provision.of.a.low.cost.and.often.high.quality.water.resource.that.is.somewhat.independent.of.short-term.climatic.variability..over.half.of.the.world’s.population.are.thought.to.depend.on.groundwater.for.every.day.uses,.such.as.drinking,.cooking.and.hygiene..Across.the.developing.world,.groundwater.accounts.for.between.about.20.and.40%.of.total.water.use..Agriculture.is.the.dominant.use.of.both.groundwater.and.surface.water.across.the.developing.world..groundwater.also.plays.a.fundamental.role.in.sustaining.many.terrestrial,.aquatic.and.even.marine.ecosystems..For.some.ecosystems,.there.is.a.highly.specialized.dependency.on.groundwater,.with.groundwater.being.the.habitat,.the.only.water.supply,.or.being.critical.to.survival.during.periods.of.seasonal.water.shortage.or.extended.episodes.of.drought.
The hidden nature of groundwater, its resilience in the face of short-term climatic variability and the difficulty in measuring it, have, among other factors, contributed to its poor management and the growing stress on groundwater resources..in.many.countries,.even.developed.countries.with.robust.surface.water.management.arrangements,.groundwater.use.is.unregulated.and.poorly.planned.and.managed..Although.data.on.the.‘health’.of.groundwater.systems.at.a.global.level.is.scant,.what.is.available.demonstrates.the.challenges.it.faces..in.several.countries.in.north.Africa.and.the.middle.east,.groundwater.allocations.exceed.average.annual.recharge.by.a.factor.of.three.times.or.more..other.developing.and.developed.countries.have.many.zones.where.groundwater.resources.have.been.depleted.(Figure.3.1)..consequences.of.this.have.already.included.supply.shortages,.subsidence,.contamination.and.decline.in.groundwater.dependent.ecosystems..As.stresses.on.surface.water.increase—due.to.both.non-climatic.and.climatic.forces—it.is.expected.that.pressure.on.groundwater.resources.will.grow.
Water security
Aggregate indices of water stress—of the type presented above—are typically in terms of annual averages, and so cannot fully capture the global impacts of hydrological
10 Waterstressexpressedasthewaterwithdrawal-to-availabilityratio.
23
variability and extremes. many.regions.of.the.world have,.what.has.been.loosely.termed,.a.‘difficult.hydrology’..this.includes.not.only.those.areas.that.confront.absolute.water.scarcity.(or.‘stress’),.but.also.those.which.suffer.from.high.inter-annual.and/or.intra-annual.hydrologic.variability.(including.extremes)..in.the.absence.of.adequate.capacity,.infrastructure.and.institutions.required.to.manage.and.mitigate.such.difficult.hydrologies,.‘water.security’.is.threatened..water.security.is.defined.as.the.availability.of.an.acceptable.quantity.and.quality.of.water.for.health,.livelihoods,.ecosystems.and.production,.coupled.with.an.acceptable.level.of.water-related.risks.to.people,.environments,.and.economies..unlike.in.the.case.of.‘water.stress,’.a.comprehensive.assessment.of.global.levels.of.water.security.has.not.been.undertaken..However,.several.regions.of.the.world.can.be.characterized.as.being.water.insecure,.either.because.of.extreme.hydrological.variability.(e.g.,.ethiopia).or.a.poor.endowment.of.water.resources.(e.g.,.yemen,.which.is.heavily.dependent.on.limited.groundwater),.or.because.of.the.dearth.of.adequate.capacity,.infrastructure.or.institutions..climate.change—which.is.projected.to.reduce.water.availability.in.regions.that.are.already.scarce.(as.discussed.above).and.increase.hydrologic.variability—is.likely.to.make.water.security.harder.to.achieve.and.maintain.
Transboundary basins
over.270.international.rivers.are.shared.by.some.90%.of.the.world’s.nations.and.territories..transboundary.river.basins.and.shared.rivers.present.both.challenges.and.opportunities.for.cooperation.and.growth..developed.economies,.in.europe.and.north.America,.have.in.most.cases.achieved.a.relative.equilibrium.in.managing.transboundary.basins.for.best.return.on.hydrology.through.transboundary.institutional.arrangements,.including.treaty.regimes.dealing.with.issues.of.river.infrastructure.and.the.quantity.and.quality.of.water.flows,.as.well.as.infrastructure.to.manage.variability.and.extreme.events..increasingly,.cooperative.efforts.are.focusing.on.the.sharing.of.benefits,.rather.than.water..the.developing.economies.sharing.river.basins.remain.challenged.by.weak.institutional.arrangements.and.inadequate.infrastructure.for.
Figure 3.1 Reported countries with groundwater depletion
Reported zones with groundwater depletion
NO
VEMBER 2009
IBRD 37364
This map was produced by the Map Design Unit of The World Bank. The boundaries, colors, denominations and any other informationshown on this map do not imply, on the part of The World BankGroup, any judgment on the legal status of any territory, or anyendorsement or acceptance of such boundaries.
Source: igrAc.global.groundwater.information.system.[http://igrac.nitg.tno.nl/ggis_map/start.html]
ManyFew None No data
24
optimum.benefit..regardless.of.the.level.of.economic.development,.climate.change.poses.a.threat.to.transboundary.basins..evidence.suggests.that.the.challenges.and.conflicts.among.the.riparian.states.depend.on.the.degree.of.variability.and.uncertainty.associated.with.the.resource.availability..Projected.changes.in.water.resources.variability.due.to.climate.change.can.impact.the.water.balance.and.consequently.the.hydropolitical.balance.in.transboundary.basins..wolf.et.al.(2003),.indicate.that.historically.extreme.events.of.conflict.over.water.have.been.more.frequent.in.water.scarce.regions.and.where.extreme.conditions.characterized.by.high.inter-annual.hydrologic.variability.occur.
water dependent sectors and climate-induced hydrologic changes
In the future, climate change could also impact water using sectors, affecting both the amount and/or quality desired (on the demand side) and/or the extent to which demands are met (on the supply/availability side).11 the.term.‘water.dependent.sectors’.is.taken.broadly.to.mean.both.water.using.sectors.(including.in-stream.and.out-of-stream,.consumptive.and.non-consumptive),.as.well.as.sectors.that.are.affected.indirectly.or.directly.by.the.water.sector.(e.g.,.health.and.transport)..in.most.countries.water.use.has.increased.in.recent.decades.due.to,.amongst.others,.population.and.economic.growth.and.changes.in.lifestyle.(including.diets)..sectoral.water.use.patterns.can.be.expected.to.continue.to.change.over.time.in.response.to.such.non-climatic.drivers,.in.addition.to.water.resource.management.and.delivery.systems.(as.discussed.above)..this.includes.not.only.infrastructure.and.technology,.but.also.institutions.that.govern.water.use.within.sectors.(e.g.,.water.pricing),.amongst.sectors.(e.g.,.water.trading),.and.even.across.national.boundaries.(e.g.,.transboundary.river.basin.agreements)..it.is.important.to.emphasize.that.changes.in.variability.could.be.as.important.as.changes.in.long-term.averages,.particularly.if.water.is.not.withdrawn.from.groundwater.bodies.or.reservoirs.
The potential impacts of climate change could extend beyond the water sector, per se, to all sectors that are linked to (or in some way dependent on) water..For.example,.pressure.on.water.supply.and.sanitation.facilities.could.have.a.wide.range.of.adverse.effects.on.human.health..reduced.availability.of.water.for.irrigation.could.threaten.food.security,.rural.development,.and.the.economies.of.countries.that.are.largely.dependent.on.the.agricultural.sector..the.potential.impact.of.climate-driven.hydrologic.change.and.increased.variability.for.some.key.water.dependent.sectors.is.discussed.below.
Health
water.is.essential.to.human.health.and.all.aspects.of.livelihood..table.3.1.shows.the.linkage.between.mediating.climate.change.factors.and.their.health.outcome..An.estimated.2.4.billion.people.are.without.access.to.proper.sanitation.and.1.billion.without.access.to.safe.drinking.water..with.projections.of.potential.decreases.in.water.availability,.these.statistics.are.likely.to.get.worse..decreasing.water.supplies.could.also.lower.the.efficiency.of.wastewater.and.sewer.systems,.leading.to.higher.concentrations.of.bacteria.and.other.micro-organisms.in.raw.water.supplies.(kabat.et.al.,.2003).
11 Theagriculturalsectoroffersagoodexampleoftheeffectsofclimatechangeonbothwaterdemandandwatersupply.IncreasingCO2concentrationscouldincreasewateruseefficiencyforsometypesofcrops,therebyreducingthedemandforirrigation(oftenreferredtoasirrigation‘requirements’).Onthesupplyside,increasedvariabilitycouldaffectthereliability/availabilityofirrigationsupplies.
25
in.addition.to.drinking.water.and.sanitation,.there.are.also.water.and.vector.borne.diseases.that.are.affected.by.climate.change.via.the.water.sector..water.plays.a.role.in.propagating.diseases.by.direct.transmission.(contamination.by.feces,.urine.or.bacteria),.inadequate.personal.hygiene,.and.parasites.using.hosts.in.or.near.the.water..decreases.in.available.supply.and.also.floods.can.increase.contamination..warming.temperatures.can.increase.the.presence.of.vector.borne.diseases.such.as.malaria.causing.higher.transmission.rates.and.new.regions.to.become.infected.
there.are.also.direct.health.effects.from.extreme.events.such.as.floods.and.droughts.which.include.changes.in.mortality.and.morbidity..Projections.show.an.increase.in.extreme.events.which.translates.into.real.losses.of.livelihoods.and.lives..some.indirect.effects.from.floods.include.overburdening.of.wastewater.and.sewer.systems,.disruption.of.safe.water.supply,.standing.water.in.low-lying.areas.(increase.in.mosquitoes.and.risk.of.malaria),.exposure.to.respiratory.and.infections,.disruption.and.increased.burden.to.medical.facilities,.and.inadequate.nutrition.following.disruption.to.incomes.and.food.distribution.systems..An.example.of.climate.change’s.impact.on.malaria.in.Africa.is.described.in.box.3.1.
Table 3.1 Mediating processes and potential effects on health of changes in temperature and weather
Mediating processes Health outcome
Direct effects
change.in.the.frequency.or.intensity.of.extreme.weather.
events,.for.example.storms,.hurricanes,.cyclones
deaths,.injuries,.psychological.disorders,.damage.to.
public.health.infrastructure
Indirect effects
changed.local.ecology.of.water.borne.and.food.borne.
infective.agents
changed.incidence.of.diarrheal.and.other.infectious.
diseases
changed.food.productivity.(especially.crops).through.
changes.in.climate.and.associated.pests.and.diseases
malnutrition.and.hunger,.and.consequent.impairment.
of.child.growth.and.development
sea.level.rise.with.population.displacement.and.
damage.to.infrastructure
increased.risk.of.infectious.disease,.psychological.
disorders
social,.economic,.and.demographic.dislocation.
through.effects.on.economy,.infrastructure,.and.
resource.supply
wide.range.of.public.health.consequences.mental.
health.and.nutritional.impairment,.infectious.diseases,.
civil.strife
Source: kabat.et..al.,.2003.pg..33;.adapted.from.mcmichael.and.Haines,.1997.
Box 3.1 Malaria in Africa under climate change
results.from.the.mapping.malaria.risk.in.Africa.project.(mArA/ArmA).indicate.changes.in.the.distribution.of.
climate-suitable.for.malaria.by.2020,.2050.and.2080..by.2050,.and.continuing.into.2080,.a.large.part.of.
the.western.sahel.and.much.of.southern-central.Africa.is.shown.to.be.likely.to.become.unsuitable.for.malaria.
transmission..other.assessments,.using.sixteen.climate.change.scenarios,.show.that,.by.2100,.changes.in.
temperature.and.precipitation.could.alter.the.geographical.distribution.of.malaria.in.Zimbabwe.with.previously.
unsuitable.areas.of.dense.human.population.becoming.suitable.for.transmission..(bates.et.al.2008).
26
indirect.health.threats.of.climate.change.include.malnutrition.from.agriculture.disruption,.infectious.diseases.spread.by.insects.and.other.vectors.advantaged.by.climate.change,.as.well.as.the.increased.risk.of.infectious.diseases.due.to.infrastructure.damage.(kabat.et.al.,.2003)..climate.changes.that.would.adversely.affect.human.health.via.the.water.sector.are.expected.to.fall.disproportionately.on.the.poor.(iPcc.2001).
Agriculture
Agriculture is by far the largest user of water, accounting for almost 70 percent of global withdrawals—and 90 percent of global consumptive water use—and up to 95 percent of withdrawals in developing countries..while.a.person.may.drink.2–4.liters.of.water.a.day,.it.takes.2,000–5,000.liters.of.water.to.produce.a.person’s.daily.food..water.is.important.for.food.security,.crop.growth,.livestock,.and.food.markets..Food.security,.defined.by.the.Food.and.Agriculture.organization.(FAo).as.the.regular.access.of.people.to.enough.high-quality.food.to.lead.active,.healthy.lives,.depends.heavily.on.water..lack.of.water.can.be.a.major.cause.of.famine.and.undernourishment,.especially.in.areas.where.people.depend.on.local.agriculture.for.food.and.livelihoods..erratic.rainfall.can.cause.temporary.food.shortages,.while.floods.and.droughts.can.lead.to.intensive.food.emergencies.
Climate change can significantly impact crop growth. changes.in.precipitation.can.alter.soil.moisture.content,.which.can.lead.to.conditions.that.are.potentially.too.dry.or.too.wet.for.viable.crop.growth.and.alter.the.need.for.and.timing.of.irrigation..Precipitation.changes.can.occur.via.extreme.events.(floods.or.droughts),.erratic.rainfall,.or.seasonal.shifts.in.runoff..there.are.critical.stages.in.a.crop’s.growth.(e.g..filling.of.the.corn.kernels).where.a.lack.of.water.during.that.short.time.can.reduce.crop.yield..rainfed.agriculture—which.supplies.over.60.percent.of.the.world’s.food—is.particularly.at.risk.
In addition to precipitation changes, increased CO2 levels and higher temperatures can affect crop growth..some.crops.may.actually.benefit.from.increased.co2.levels,.while.other.plants.will.not..in.general,.higher.temperatures.are.associated.with.higher.radiation.and.higher.water.use.which.could.put.stress.on.overall.water.availability..it.is.expected.that.higher.temperatures.will.promote.more.plant.growth.at.high.latitudes.and.altitudes.(northern.regions.of.former.soviet.union,.canada,.and.europe)..the.higher.yields.are.primarily.due.to.longer.growing.season.and.mitigating.the.negative.cold.weather.effects.on.plant.growth.(kabat.et.al.,.2003)..northern.middle.latitude.countries.(us,.western.europe,.and.most.of.canada).are.expected.to.see.negative.effects.on.crop.and.livestock.productivity.due.to.increased.temperatures.and.increased.evapotranspiration.(shortening.of.the.growing.season)..taken.together,.higher.temperatures.and.increased.variability.of.precipitation.would,.in.general,.lead.to.increased.irrigation.water.demand,.even.if.total.precipitation.during.the.growing.season.remains.the.same.(bates,.et.al.,.2008).
Food markets are affected by climate change..As.mentioned.previously.climate.change.and.variability.can.lead.to.decreases.in.food.production..these.shortfalls.create.market.imbalances,.which.push.international.prices.upwards.and.provide.incentives.for.reallocation.of.capital.and.human.resources,.thus.reducing.climate-change.impacts.by.economic.adjustments..the.gdP.of.the.agricultural.sector.in.developing.regions,.with.the.exception.of.latin.America,.will.be.negatively.impacted.by.climate.change.(kabat.et.al.,.2003.).this.is.due.to.the.lack.of.high-tech.solutions.that.can.meet.the.needs.of.the.poorer.farmers,.who.most.often.partake.in.rainfed.agriculture.
27
Key drivers for future irrigation water demand are the extent of irrigated area, unit water use, cropping intensity, and irrigation water-use efficiency..According.to.the.Food.and.Agriculture.organization.(FAo).agriculture.projections.for.2030.suggest.that.developing.countries.are.likely.to.continue.to.expand.their.irrigated.area.and.to.increase.cropping.intensity.(e.g.,.double.cropping).while.irrigation.water-use.efficiency.will.increase.slightly..climate.change.will.worsen.these.estimates..most.of.this.expansion.is.projected.to.occur.in.already.water-stressed.areas,.such.as.southern.Asia,.northern.china,.the.near.east,.and.north.Africa..After.2050,.the.irrigated.area.is.assumed.to.stabilize.or.to.slightly.decline.in.most.cases.
Industry and transport sector
Many industries depend on water to create their product. Beverage companies require a reliable source of water that meets a strict quality..other.industries.use.water.in.their.manufacturing.process..some.power.industries.use.water.for.cooling..the.ski.industry.relies.on.snowpack/glacier.stability.for.operation.which.can.be.directly.affected.by.climate.change..changes.to.the.availability.of.water.will.greatly.affect.the.success.of.these.industries..most.of.the.industries.will.release.the.water.after.they.have.used.it.into.streams.for.future.use..there.is.a.certain.standard.that.the.effluent.from.the.industry.must.meet.both.in.temperature.and.quality..Predictions.of.lower.stream.flows.would.have.a.major.effect.on.effluent.standards..industries.would.have.to.spend.more.time.and.money.producing.higher.quality.effluent.to.meet.standards.
Transport sector has close links with the water sector..transportation.via.water.is.directly.affected.by.water.levels.in.navigable.rivers..decreases.in.river.flow.will.potentially.reduce.and/or.eliminate.transportation.via.waterways..other.transportation.means.including.roads.and.bridges.and.railways.and.subways.will.be.most.affected.by.extreme.events.such.as.flooding..impacts.on.transportation.have.a.direct.affect.on.livelihoods;.including.the.ability.for.people.to.get.access.to.necessary.food.and.water,.and.make.a.living.
Energy/Hydropower
Hydropower generation is the energy source most likely to be impacted by climate change and climate variability because it directly deals with water quantity and timing..An.example.of.hydropower.being.negatively.impacted.by.climate.change.is.described.in.box.3.2.for.the.Zambezi.basin..A.side.note.on.climate.change’s.impact.on.the.demand.for.energy.is.that.while.it.is.likely.there.will.be.an.increased.energy.demand.for.space.cooling.due.to.higher.summer.temperatures,.there.will.also.likely.be.a.decreased.energy.demand.for.space.heating.due.to.higher.winter.temperatures.(kabat.et.al.,.2003).
A reduction in river flow results in a decrease in hydropower production..First.because.there.is.less.water.going.through.the.turbines.and.second.because.the.lower.water.levels.reduce.the.water.pressure.and.the.amount.of.power.that.can.be.produced..while.hydroelectric.projects.are.designed.for.a.specific.flow.regime,.including.a.margin.of.safety;.projected.climate.changes.are.expected.to.change.those.flow.regimes,.in.some.instances.to.a.point.outside.the.current.safety.margins..this.will.result.in.a.need.to.retrofit.current.structures.or.tear.down.and.build.new.hydroelectric.projects..with.more.intense.rainfall.events.as.suggested.in.climate.projections,.more.conservative.water.storage.strategies.will.be.necessary.to.prevent.flood.damage.resulting.in.a.decrease.in.using.full.hydropower.potential.because.reservoirs.will.not.be.kept.full..the.projected.increase.in.droughts.will.also.require.more.conservative.water.storage.strategies.and.may.
28
decrease.the.amount.of.water.available.to.release.for.hydropower..lastly,.with.less.precipitation.falling.as.snow,.there.will.be.less.water.available.during.warm.months.when.energy.demand.is.highest.(kabat.et.al.,.2003).
Natural ecosystems
Freshwater ecosystems are essential components of the environment. climate.change.potentially.affects.the.water.sector.via.direct,.indirect,.and.synergistic.impacts.with.non-climate.forces..each.of.these.will.have.significant.impacts.on.freshwater.ecosystems..A.change.in.the.variability.or.trend.of.climatic.conditions.also.impacts.the.environment.as.seen.in.southern.Africa..direct.impacts.of.reduced.rainfall.and.increased.temperature.include.lower.flows.in.rivers,.lower.level.in.water.tables,.lower.rates.of.groundwater.recharge,.and.higher.temperatures.in.rivers.and.lakes..direct.climate.change.impacts.on.water.quantity,.timing,.and.quality.regimes.are.also.expected.to.affect.the.performance.and.operation.of.existing.and.planned.water.infrastructure—including.water.storage.and.transfer,.hydropower,.structural.flood.defenses,.urban.drainage,.water.supply,.and.irrigation.systems.
indirect.impacts.of.the.climate.changes.include.the.following.(kabat.et.al.,.2003):
•.disruption.of.flowering.phenology•.shifts.in.vegetative.season•.species.invasions•.changes.in.productivity.of.the.ecosystem•.shifts.in.nutrient.cycles.related.to.fluctuations.in.
water.levels•.changes.or.declines.in.hydrological.connectivity.that.can.lead.to.loss.of.habitat.critical.to.faunal.
life.stages,.i.e..fish•.occurrence.and/or.shifts.in.intensity.and.frequency.of.structuring.processes.(fire,.flood,.pests)
In addition, societal responses to anticipated climate threats could indirectly affect aquatic environments through new infrastructure development (e.g., to meet targets for renewable energy and reduce greenhouse gas emissions, or to protect against flooding), and changes in land use (e.g., to adapt to changed growing seasons and/or water availability, or to cultivate new crops such as bio-fuels)12. Finally,.non-climatic.pressures.on.freshwaters.linked.to.population.and.economic.growth,.or.to.land.use.change,.could.be.amplified.by.climate.change..For.example,.higher.volumes.of.groundwater.abstraction.associated.with.coastal.zone.development.will.hasten.ingress.of.saltwater.to.shallow.aquifers.that.are.also.at.risk.from.rising.sea.levels.
Changes to the ecosystem can also impact human livelihoods such as ecotourism and fishing..in.addition,.ecosystem.changes.can.impact.human.health..For.example,.decreasing.fish.populations.can.diminish.the.main,.if.not.only,.protein.source.for.a.human.community.
Box 3.2 Hydropower in Zambezi Basin under climate change
A.study.of.hydro-electric.power.generation.
conducted.in.the.Zambezi.basin,.taken.in.
conjunction.with.projections.future.runoff,.
indicate.that.hydropower.generation.would.
be.negatively.affected.by.climate.change,.
particularly.in.river.basins.that.are.situated.in.
sub-humid.regions.(bates.et.al.2008).
12 SeeforexampleasectorbysectorreviewforEuropeBerry,P.,Paterson,J.,Cabeza,M.etal.2008.Mitigation measures and adaptation measures and their impacts on biodiversity.MinimisationofandAdaptationtoClimatechange:ImpactsonBiodiversity(MACIS).OxfordUniversity,320pp.
29
impact of non-climatic drivers on water availability and use patterns
Non-climatic factors could aggravate or attenuate the adverse effects of climate change on surface water and groundwater availability, as well as have a significant influence on water use..Population.growth,.food.consumption.(including.type.of.diet),.economic.development.(and.by.extension,.changes.in.lifestyles.and.societal.views.on.the.value.of.water),.technology,.and.economic.policy.(including.water.pricing.and.trade.in.‘virtual.water’).will.play.a.major—if.not.dominant—role.in.influencing.water.use.patterns.
Non-climatic factors are likely to have significant adverse effects on surface water and groundwater quality. These could be aggravated by climate change..industrial.development,.run-off.from.agriculture,.and.un-treated.sewerage.from.agglomerations.already.impact.adversely.on.the.quality.of.water..the.world.bank.recently.estimated.the.negative.effect.of.water.pollution.on.gdP.in.china.to.be.1%.annually,.the.threat.of.arsenic.pollution.in.drinking.water.in.bangladesh.and.other.places.has.been.exacerbated.by.over.extraction..these.effects.may.be.aggravated.by.climate.change.if.flows.and.groundwater.recharge.is.diminished.and/or.water.demand.is.increased.
Human activities significantly influence water availability and land use, as well as critically impact the existing and future water resource management and delivery systems. systems.for.delivering.water.services.include.irrigation;.urban.water,.sanitation.and.drainage;.rural.water.and.sanitation;.and.ports.and.navigation..systems.for.managing.water.resources.include.those.for.delivery.of.bulk.irrigation.water,.watersheds,.and.water.resources.broadly,.as.well.as.multi-purpose.systems.(including.hydropower).and.flood.control..As.indicated.earlier,.the.term.‘system’.is.intended.to.capture.all.elements—from.infrastructure.to.institutions—that.contribute.to.performance.of.the.intended.function.
The impact of climate change could carry significant negative consequences for existing water resource management and delivery systems..For.example,.in.urban.environments,.more.heavy.rainfall.events.could.overload.the.capacity.of.storm.drain.systems.and.water.and.wastewater.treatment.facilities;.sea.level.rise.could.lead.to.salinization.of.water.supplies.from.coastal.aquifers..climate.change.could.increase.irrigation.demand.due.to.the.combination.of.decreased.rainfall.and.increased.evapotranspiration,.placing.additional.pressure.on.irrigation.systems.that.are.in.many.cases.already.under.performing..changes.in.river.flows.could.have.a.direct.impact.on.hydropower.generation.facilities..soil.erosion.from.increased.rainfall.intensity.could.affect.watershed.sustainability.and.lead.to.sedimentation.in.reservoirs,.impacting.on.the.operation.of.
Box 3.3 Fate of ecosystems in Southern Africa under climate change
by.2050,.the.Fynbos.biome.(ericaceae-dominated.ecosystem.of.south.Africa,.which.is.an.iucn.‘hotspot’).is.
projected.to.lose.51–61%.of.its.extent.due.to.decreased.winter.precipitation..the.succulent.karoo.biome,.which.
includes.2,800.plant.species.at.increased.risk.of.extinction,.is.projected.to.expand.south-eastwards,.and.about.
2%.of.the.family.Proteaceae.are.projected.to.become.extinct..these.plants.are.closely.associated.with.birds.that.
have.specialized.on.feeding.on.them..some.mammal.species,.such.as.the.zebra.and.nyala,.which.have.been.
shown.to.be.vulnerable.to.drought.induced.changes.in.food.availability,.are.widely.projected.to.suffer.losses..
in.some.wildlife.management.areas,.such.as.the.kruger.and.Hwange.national.Parks,.wildlife.populations.are.
already.dependent.on.water.supplies.supplemented.by.borehole.water.(bates.et.al.,.2008).
30
multi-purpose.facilities..extreme.variability.and/or.reduced.supplies.could.stretch.the.infrastructural.and.institutional.limits.of.systems.that.manage.water.across.sectors.and.even.national.boundaries..some.of.the.non-climatic.factors,.as.identified.by.iPcc.are.given.in.box.3.4.
Box 3.4 Non-climatic drivers of change in freshwater systems
in.addition.to.the.discussion.of.hydrologic.and.climatic.impacts,.there.are.also.many.non-climatic.drivers.
of.freshwater.systems..For.example,.water.use.is.driven.by.changes.in.population,.food.demand,.economy,.
technology,.lifestyle,.and.societal.views.regarding.value.of.freshwater.ecosystems..land.use.change,.construction.
and.management.of.reservoirs,.pollutant.emissions,.and.water.and.waste.water.treatment.all.influence.both.the.
quantity.and.quality.of.freshwater..Also,.water.management.(i.e.,.how.a.reservoir.releases.water,.what.demands.
have.priority,.etc.).plays.a.major.role.in.the.vulnerability.of.a.water.system.both.at.the.national.and.international.
level.(bates.et.al.2008).
31
CHaPTer 4: THe CosT of vulnerabiliTy To HydrologiC CHange and inCreased variabiliTy
The developing world is particularly vulnerable to climate change
The impacts of a changing climate on the hydrologic cycle will be felt in developed and developing countries alike. However,.many.parts.of.the.developing.world.are.particularly.vulnerable..vulnerability.to.climate.change.has.been.defined.by.iPcc.as.the.degree.to.which.geophysical,.biological.and.socioeconomic.systems.are.susceptible.to,.or.unable.to.cope.with,.adverse.effects.of.climate.change,.including.climate.variability.and.extremes..it.is.a.function.of,.amongst.others,.the.character,.magnitude.and.rate.of.climate.variation.to.which.a.system.is.exposed,.its.sensitivity.and.its.adaptive.capacity..the.financial.cost.of.vulnerability.is.difficult.to.assess.and.even.more.difficult.is.the.cost.of.adaptation.to.uncertain.future..work.is.in.progress.to.address.financial.costs..Here,.the.focus.is.primarily.on.the.non-financial.costs.
A number of factors make many developing countries—and the poorest within them—particularly vulnerable to the potentially adverse impacts of climate change. these.include.weak.institutions.and.limited.institutional.capacity,.high.levels.of.poverty,.insufficient.stock.of.water.management.and.services.infrastructure,.lack.of.access.to.technology.and.capital.to.invest.in.risk.reduction,.and.dependence.on.climate-sensitive.sectors.such.as.agriculture,.forestry.and.fisheries..more.precisely,.several.factors,.both.physical.features.and.societal.characteristics,.have.been.associated.with.high.levels.of.vulnerability.(Arnell,.2003)..these.include:
•.Physical.Features•.A.current.hydrological.and.climatic.regime.that.is.marginal.for.agriculture.and.livestock•.Highly.seasonal.hydrology.as.a.result.of.either.seasonal.precipitation.or.dependence.on.
snowmelt•.High.rates.of.sedimentation.of.reservoir.storage•.topography.and.land-use.patterns.that.promote.soil.erosion.and.flash.flooding.conditions•.lack.of.variety.in.climatic.conditions.across.a.region,.leading.to.inability.to.relocate.activities.
in.response.to.climate.change
•.societal.characteristics•.Poverty.and.low.income.levels,.which.prevent.long-term.planning.and.provisioning.at.the.
household.level
•.lack.of.infrastructure,.or.poor.maintenance.and.deterioration.of.existing.infrastructure
•.lack.of.human.capital.skills.for.system.planning.and.management
•.lack.of.appropriate,.empowering.institutions
•.Absence.of.appropriate.land-use.planning
•.High.population.densities.and.other.factors.that.inhibit.population.mobility
•.increasing.demand.for.water.because.of.rapid.population.growth
•.conservative.attitudes.toward.risk.(unwillingness.to.live.with.some.risk.as.a.tradeoff.against.more.goods.and.services)
•.lack.of.formal.links.among.various.parties.involved.in.water.management
32
many,.if.not.all,.of.the.above.factors.are.prevalent.in.the.developing.world,.and.so.the.implications.of.climate.change.are.likely.to.be.greatest.here..indeed,.this.is.precisely.the.finding.of.the.more.rigorous.‘vulnerability.assessments,’.which.are.presented.below.
Vulnerability to surface water stress
Several attempts have been made to estimate vulnerability on a global scale..this.is.done.by.incorporating.some.proxy.for.adaptive.capacity.(‘economic.coping.capacity’,.raskin.et.al,.1997;.the.Human.development.index,.Alcamo.and.Heinrichs,.2002)..Perhaps.the.most.comprehensive.is.the.climate.vulnerability.index.(cvi),.which.is.an.extension.of.the.water.Poverty.index..six.major.components.are.included.in.the.cvi—resource,.access,.capacity,.use,.environment,.and.geospatial—each.of.which.is.comprised.of.several.variables..Figure.4.1.compares.vulnerabilities.of.different.regions.at.present.and.how.they.might.be.affected.over.the.next.thirty.years..As.can.be.seen,.most.of.the.developing.world.falls.in.the.range.of.medium.to.high.vulnerability.
Vulnerability to groundwater stress
A preliminary assessment of the vulnerability of groundwater in World Bank regions to climate change was recently undertaken by the World Bank (World Bank, 2009b)..vulnerability.is.assessed.for.2050,.assuming.all.non-climatic.conditions.as.current..the.assessment.is.at.regional.scale.and.is.intended.as.a.general.indicator.only..Four.criteria.were.considered.in.the.regional.vulnerability.assessment.(table.4.1):
•.current.level.of.exploitation.of.groundwater.resources—as.indicated.by.the.use.of.groundwater.relative.to.average.annual.recharge.(after.igrAc,.2004);
Figure 4.1 Some preliminary results for applying the Climate Vulnerability Index (CVI) for comparison of vulnerability by region at present and in 30 years
NO
VEMBER 2009
IBRD 37365
This map was produced by the Map Design Unit of The World Bank. The boundaries, colors, denominations and any other informationshown on this map do not imply, on the part of The World BankGroup, any judgment on the legal status of any territory, or anyendorsement or acceptance of such boundaries.
2030 78.5 0.0 8.8 53.6 53.2 35.8 38.32000 67.8 0.0 10.2 46.3 45.6 35.8 34.3
Barbados R A U GC E
R A U GC E
R A U GC E
CVI
2030 47.5 6.6 28.4 61.0 50.4 59.7 42.32000 32.1 26.3 42.0 42.9 43.2 54.7 40.2
Bolivia CVI
2030 64.0 7.8 33.7 50.7 78.0 86.8 53.52000 55.1 31.0 49.6 38.3 55.2 76.7 50.1
Bangladesh CVI
Examining potential change using the CVIillustrating change in future component values
Source: sullivan.and.meigh,.2005.and.sullivan.and.Huntingford,.2009
key to Cvi components: r- resources, a- access, C- Capacity, u- use, e- environment, g- geospatial
High (52.0–60.0)Medium high (44.0–51.9)Medium (36.0–43.9)Medium low (28.0–35.9)Low (20.0–27.9)No data
33
•.the.magnitude.and.trend.in.changes.in.rates.of.groundwater.recharge.under.2050.climate.change.projections.(after.döll.and.Flörke,.2005);
•.the.exposure.of.regional.water.resources.to.sea.level.rise.and.contamination.due.to.storm.surge.(based.on.the.authors’.assessment.of.cyclone.incidence,.the.extent.of.coastal.areas.in.the.region.and.population.density.in.these.areas);
•.wealth,.as.measured.by.per.capita.gross.national.income.(gni;.world.bank,.200813)
Groundwater utilization is used as an indicator of sensitivity to climate change..the.second.and.third.criteria.were.indicators.of.exposure.and.gni.was.used.to.indicate.adaptive.capacity..these.factors.were.combined.to.provide.a.vulnerability.indicator..Adaptive.capacity.and.the.combination.of.exposure.and.sensitivity.indicators.were.weighted.evenly..weighting.to.sea.level.rise.and.storm.surge.risk.was.reduced.to.reflect.its.uneven.application.to.world.bank.regions.
While there remains significant uncertainty with this assessment, it suggests that groundwater in the World Bank Europe and Central Asia region is the least vulnerable to
Table 4.1 Preliminary assessment of vulnerability of groundwater in World Bank regions to climate change
World Bank
region
Sensitivity Exposure Adaptive capacity
Utilisation of
groundwater
Climate
change
impact on
recharge
SLR1 &
storm surge
exposure
Per capita
GNI1 Vulnerability2
east.Asia.&.
Pacific
moderate increase medium moderate moderate
europe.&..
central.Asia
low increase low High low
latin.America.&.
caribbean
moderate reduction medium moderate moderate
middle.east.&.
north.Africa
High uncertain low moderate moderate
south.Asia moderate negligible High low High
sub-saharan.
Africa
moderate reduction low low High
1.slr—sea.level.rise;.gni—gross.national.income.(in.$us)2.vulnerability.assessed.from.the.sum.of.average.of.sensitivity.and.exposure.ratings.and.adaptive.capacity.rating.
•. groundwater.utilisation—low.(2),.moderate.(4),.high.(6)•. impact.on.recharge—increase.(2),.uncertain/negligible.(4),.reduction.(6)•. slr.exposure—low.(1),.medium.(2),.high.(3)•. Per.capita.gni—low.(6),.moderate.(4),.high.(2)—relative.to.each.other
low.vulnerability.(<6),.moderate.(6–9),.High.(>9)Additional.note:.Although.such.a.regional.scale.analysis.masks.country-to-country.differences.in.vulnerability—which.are.expected.to.be.large—it.provides.some.insight.into.potential.‘hot.spots’.of.climate.change.vulnerability.
13 Datafromhttp://go.worldbank.org/GKIIAZEJR0
34
the effects of climate change..this.reflects.the.relatively.low.level.of.utilization.of.groundwater,.the.projected.increase.in.rainfall.(in.many.areas),.minimal.exposure.of.groundwater.to.risks.from.sea.level.rise.and.storm.surge.and.higher.per.capita.income..groundwater.resources.in.the.south.Asia.and.sub-saharan.Africa.regions.were.considered.to.be.most.vulnerable.
Costs to the most vulnerable
The most vulnerable regions of the world are already suffering huge costs associated with climate and hydrologic variability, and this could be worsened by longer-term changes in climate. in.particular,.the.incidence.and.severity.of.both.floods.and.droughts.has.been.growing.globally,.as.have.the.economic,.social.and.environmental.damages.associated.with.them..yearly.economic.losses.from.large.extreme.events—including.floods.and.droughts—have.increased.ten-fold.between.the.1950s.and.1990s..From.1990.to.1996.alone,.there.were.six.major.floods.throughout.the.world.in.which.the.number.of.fatalities.exceeded.1,000.and.22.floods.with.losses.exceeding.us$1.billion.each.(kabat.et.al.,.2003)..the.developing.world—and.particularly.in.south.and.east.Asia—have.been.the.worst.hit.by.disastrous.floods..Although.part.of.the.increase.in.losses.is.attributable.to.socio-economic.factors—including.population.growth,.expansion.into.flood.prone.areas,.land.use.changes,.manipulation.of.water.within.channels—climatic.factors.are.also.partly.responsible..droughts.have.been.equally.devastating,.particularly.in.Africa,.which.has.been.exposed.to.more.recurrent.droughts.than.any.other.part.of.the.world..Again,.non-climatic.factors—including.poor.management.of.water.resources,.urbanization.and.degrading.watersheds,.and.in.the.worst.cases,.civil.war—have.played.a.significant.role.in.increasing.vulnerabilities.to.drought.
Studies that have assessed the economic impacts of climate variability—and in particular floods and droughts—in the developing world have found these to be substantial. one.of.the.earliest.study.estimated.the.cost.to.kenya.of.two.extreme.events,.finding.that.the.1997/8.el.niño.floods.cost.the.country.11.percent.of.its.gdP.and.the.1998/2000.la.niña.drought,.16.percent.(world.bank,.2004)..According.to.the.study,.given.their.regularity.and.over.the.long.term,.floods.and.droughts.are.estimated.to.cost.kenya.about.2.4.percent.of.gdP.annually,.and.water.resources.degradation.a.further.0.5.percent.of.the.gdP.annually,.representing.a.serious.drag.on.the.country’s.economy..the.calculation.of.annualized.cost.was.based.on.the.frequency.and.intensity.of.historical.floods.and.droughts..As.these.are.likely.to.become.more.pronounced.with.climate.change,.economic.costs.can.be.expected.to.be.even.more.substantial.in.the.future,.all.else.equal..in.ethiopia,.economy-wide.models.incorporating.hydrological.variability.show.that.the.projections.of.average.annual.gdP.rates.drop.by.as.much.as.38.percent,.as.compared.to.when.hydrological.variability.is.not.included.(mogaka.et.al.,.2006)..the.economy—heavily.dependent.on.rainfed.agriculture—was.found.to.be.so.intimately.tied.to.hydrological.variability.that.even.a.single.drought.event.within.a.twelve.year.period.would.diminish.average.growth.rates.across.the.entire.twelve.year.period.by.10.percent..both.of.these.cases.have.‘difficult.hydrologies’..However,.it.is.not.hydrological.variability.per.se—but.extreme.vulnerability.to.it.due.to.a.lack.of.the.‘minimum.platform’.of.necessary.capacity,.infrastructure.and.institutions.to.mitigate.the.impacts—that.makes.them.water.insecure..As.just.one.indicator,.installed.reservoir.capacity.per.capita.is.only.40.m3.in.ethiopia.(a.nation.with.greater.climate.variability).as.compared.to.over.6000.m3.in.north.America.(an.area.with.much.less.climate.variability).
Climate change is projected to alter the amount, intensity and frequency of precipitation, directly affecting not only the magnitude and timing of floods and droughts, but also runoff patterns, groundwater recharge, and water quality..For.example,.glacial.meltdown.in.
35
several.regions.of.the.world—including.the.Andes.and.the.Himalayas—is.already.occurring.and.the.rate.is.projected.to.increase.with.a.continual.warming.of.the.climate..the.Himalaya.glaciers.are.reducing.at.a.rate.of.33–49.feet.per.year..glacial.melt.is.expected.to.lower.water.levels.in.river.basins,.including.the.indus.and.the.ganges,.by.as.much.as.two-thirds,.affecting.over.500.million.people.in.india..on.a.per.capita.basis,.water.availability.is.projected.to.decline.by.over.30.percent.in.the.next.four.decades..india.has.one.of.the.world’s.most.ambitious.hydropower.programs,.but.there.might.not.be.sufficient.water.available.to.run.the.new.turbines.by.the.time.that.the.dams.are.built..india’s.megacities.in.coastal.areas—such.as.mumbai.and.chennai—are.also.at.risk..some.experts.have.estimated.that.india’s.gdP.could.drop.by.as.much.as.nine.percent,.largely.due.to.submergence..it.is.estimated.that.mumbai.alone.could.lose.up.to.$48.billion.(tehelka,.2008).
implications for sustainable development and the bank’s mission for poverty reduction
For regions that are already highly vulnerable to climate variability, the potential impacts on all sectors that depend on water—from domestic water supply and agriculture to health and the environment—could strain economies and livelihoods..in.many.regions.of.the.globe,.climate.change.may.put.at.risk.progress.that.has.been.made.over.several.decades.in.sustainably.developing.economies.and.societies..indeed,.according.to.the.iPcc,.“even.with.optimal.water.management,.it.is.very.likely.that.the.negative.impacts.on.sustainable.development.cannot.be.avoided”.(bates,.et.al.,.2008)..Figure.4.2.shows.some.key.cases.around.the.world.where.water-related.climate.change.impacts.on.various.sectors.and.systems.are.a.threat.to.the.sustainable.development.of.affected.regions.
The current financial crisis and various sector crises have already and will continue to impact financing of adaptation to climate change..A.theme.that.has.been.emphasized.throughout.this.report.is.that.climate.change.is.not.the.only—or.even.the.primary—factor.exerting.stress.on.the.water.sector,.and.by.extension.societies,.economies,.and.the.environment..the.current.financial.crisis.and.the.sector.crises.(e.g.,.rising.food.prices,.energy.cost).have.forced.many.governments.in.developing.countries.to.defer.urgent.operation.and.maintenance,.as.well.as.water.investment.needs..this.can.exacerbate.efforts.of.the.governments.in.tackling.their.current.water.challenges,.such.as.provision.of.safe.drinking.water.and.improved.sanitation,.jeopardizing.achievement.of.the.millennium.development.goals.targets..the.private.sector.capital.flight.is.expected.to.continue.in.these.financially.uncertain.times,.affecting.investment.decisions.with.climate.adaptation.aspects..in.the.near-.to.medium-term,.the.situation.is.expected.to.worsen.unless.investment.funds.are.channeled.to.the.sector..Here,.a.combination.of.the.new.financial.and.climate.change.architectures.such.as.the.vulnerability.Fund,.the.climate.investment.Fund,.and.other.mechanisms.to.alleviate.the.investment.bottle.neck.should.be.made.available.to.the.client.bank.countries..this,.at.a.minimum,.can.help.protect.infrastructure.assets.through.coverage.of.cost.of.operation.and.maintenance..current.hydrologic.variability.and.magnitude.and.frequency.of.extreme.events.may.make.meeting.water-related.mdgs.(targets.1,.6.and.7).by.2015.more.difficult..but.it.is.highly.unlikely.that.these.alone.will.hamper.achievement..the.significance.of.climate.change.lies.in.its.interaction.with.other.pressures,.both.current.and.future..making.systems,.societies.and.economies.less.vulnerable.to.the.potential.impacts.requires.that.climate.change.be.addressed.within.this.broader.context..viewed.in.the.long.term,.the.current.financial.crisis.and.the.stimulus.packages.to.respond.to.this.crisis.can.be.designed.to.take.into.account.the.wider.risk.of.climate.change.in.the.recovery.and.rebuilding.process.
36
Figure 4.2 Illustrative map of future climate change impacts related to freshwater which threaten the sustainable development of the affected regions
1:.bobba.et.al..(2000),.2:.barnett.et.al..(2004),.3:.doll.and.Floke.(2005),.4:.mirza.et.al..(2003),.5:.lehmer.et.at..(2005).6:.kistemannet.al..(2002),.7:.porter.and.semenov.(2005)..background.map:.ensemble.mean.change.of.annual.runoff,.in.percent,.between.present.(1980–1999).and.2090–2099).for.the.sres.A1b.emissions.scenarios.(based.on.milly.et.al.,.2005)..Areas.with.blue.(red).colors.indicate.the.increase.(decrease).of.annual.runoff..[bates.et.al,.2008,.Fig..3.4.pg..47]
37
CHaPTer 5: ClimaTe and Hydrology ProjeCTions for invesTmenT deCisions
introduction
The purpose of these projections is to gain insight into potential future hydrology and to establish a common platform of information on the behavior of key hydrologic drivers across World Bank regions at a scale appropriate for policy and investment decisions..the.catchment.level.was.selected.because.it.is.the.most.appropriate.scale.for.water.planning.and.investment..Projected.impacts.on.runoff.and.basin.yield,.extreme.events.(floods.and.droughts),.minimum.base.flow.(a.proxy.for.groundwater.recharge),.and.net.irrigation.demand.are.assessed.here,.as.these.variables.are.particularly.relevant.for.water.planning.and.investments..the.methodological.approach.used.for.this.analysis.was.developed.to.explicitly.tackle.two.difficult.issues.that.plague.climate.change.assessments:.(i).how.to.‘match’.model.outputs.generated.at.a.course.resolution.with.the.desired.(and.typically.finer).scale.and.(ii).how.to.take.advantage.of.all.information.generated.from.climate.models,.specifically.by.capturing.the.full.spectrum.of.model.projections..twenty-two.gcms.along.with.three.emissions.scenarios.(A1b,.A2.and.b1).are.used.to.analyze.changes.in.the.key.hydrologic.variables.in.the.years.2030.and.2050..For.each.world.bank.region,.the.wettest,.driest.and.a.middle.scenario.are.identified.based.on.the.climate.moisture.index..these.scenarios.serve.as.the.basis.for.estimating.changes.in.the.key.hydrologic.variables.
key issues in climate change impact assessments
Resolution and scale in impact assessments
One potential difficulty with using climate information in impact assessments—including in the water sector—is the ‘mis-match’ between the low spatial (and temporal) resolution of GCMs, on the one hand, and the scale at which assessments need typically to be conducted for investment purposes, on the other..gcms.provide.climate.change.projections.at.a.low.spatial.resolution.(~2.5˚.x.2.5˚.grid;.table.5.1).while.water.planning.and.management.analyses.often.require.a.much.finer.resolution.(~0.5˚.x.0.5˚.grid.or.even.finer.for.project.level.analyses)..table.5.2.provides.a.list.of.areas.for.1˚grid.cells.at.various.latitudes.for.reference..the.goal.of.the.assessment—i.e..what.is.it.trying.to.answer;.who.is.it.trying.to.inform?—should.drive.the.decision.on.both.the.relevant.scale,.and.the.most.appropriate.technique.to.use.for.matching.gcm.output.with.that.scale.
There are several methods available for addressing scale issues,.including.statistical.downscaling.(using.empirical.relationships),.dynamical.downscaling.(using.regional.climate.models).and.‘spatial.techniques’14.(linear.interpolation,.krigging,.spline.fitting,.and.intelligent.interpolation). downscaling.involves.methods.used.to.map.the.large.scale.signals.from.gcms.to.a.finer.resolution.(tens.of.kilometers.versus.hundreds.of.kilometers).
Care needs to be taken in selecting the method of analysis..beyond.reproducing.the.underlying.uncertainties.of.gcms,.many.introduce.additional.uncertainty.and.biases..For.example,.downscaling.techniques.increase.the.detail.of.information,.but.also.the.uncertainties.associated.with.that.information.due.to.fact.that.the.gcm.output.is.manipulated.below.the.scale.at.which.
14 ‘Spatialtechnique’isoftenandcommonlyreferredtoas‘spatialdownscaling’buttechnicallydoesnotinvolvedownscalingalgorithm.Themajorityof‘downscaling’beingdoneiswiththismethod.
38
Table 5.1 Spatial Resolution of AR4 IPCC Archived GCMs
GCM Latitude Longitude Area at 40° lat (km2)
bccr_bcm2_0 2.81 2.81 75,115
cccma_cgcm3_1 3.75 3.75 133,538
cccma_cgcm3_1_t63 2.81 2.81 75,115
cnrm_cm3 2.81 2.81 75,115
csiro_mk3_0 1.88 1.88 33,384
csiro_mk3_5 1.88 1.88 33,384
gfdl_cm2_0 2 2.5 47,480
gfdl_cm2_1 2 2.5 47,480
giss_aom 3 4 113,952
giss_model_e_h 3.91 5 185,792
giss_model_e_r 3.91 5 185,792
iap_fgoals1_0_g 3 2.81 80,123
inmcm3_0 4 5 189,920
ipsl_cm4 2.5 3.75 89,025
miroc3_2_hires 1.13 1.13 12,018
miroc3_2_medres 2.81 2.81 75,115
mpi_echam5 1.88 1.88 33,384
mri_cgcm2_3_2a 2.81 2.81 75,115
ncar_ccsm3_0 1.41 1.41 18,779
ncar_pcm1 2.81 2.81 75,115
ukmo_hadcm3 2.47 3.75 87806
ukmo_hadgem1 1.24 1.88 22,103
Average 2.6 3 72,420
Table 5.2 Coverage area of 1-degree latitude by 1-degree longitude
Latitude
1 Degree Longitude
km
1 Degree Latitude
km
1 Square Degree
e km2
0 111 111 12,393
40 85 111 9,496
60 56 111 6,181
80 17 111 1,876
39
the.physics.of.the.gcm.itself.are.mathematically.described..under.some.downscaling.schemes,.mass.balances.of.water.and.energy.over.the.gcm.scale.are.violated.by.the.downscaling.algorithm..use.of.dynamical.and.statistical.downscaling.techniques.requires.extensive.quantification.of.the.sensitivities.of.the.underlying.assumptions.of.both.the.gcms.and.the.downscaling.algorithms,.resulting.in.the.need.for.exhaustive.numerical.experimentation..time.and.cost.constraints.often.do.not.allow.use.of.more.than.a.couple.of.gcms.in.downscaling.exercises..running.multiple.gcms.at.a.coarse.resolution.may.provide.more.insight.into.the.range.of.possible.futures.than.more.detailed.information.obtained.from.fewer.gcms.
There is no one ‘best’ method; the most appropriate method for a particular application will strike a careful balance between precision (resolution) and accuracy (confidence in projections)..Figure.5.1.provides.a.visual.representation.of.the.trade-off.between.precision.and.accuracy..As.resolution.increases,.so.does.the.uncertainty.associated.with.the.more.detailed.information..in.other.words,.more.‘precise’.information.comes.at.a.cost,.and.the.additional.uncertainty.must.be.recognized.and.taken.into.account.in.assessing.impacts..given.the.trade-off,.it.is.critical.to.establish.at.the.outset.of.any.impact.assessment.whether.the.goal.is.to.have.finer.resolution.or.‘better’.(that.is,.more.reliable).information.
In this analysis, the catchment level is selected as it is the most appropriate scale for water planning and investment..this.analysis.does.not.employ.dynamical.or.statistical.downscaling.techniques.for.the.reasons.stated.above..instead,.projections.from.22.gcms.and.3.sress.were.applied.at.their.native.spatial.grid.scale.(~2.5˚.x.2.5˚),.and.the.changes.in.climate.variables.between.the.model.runs.and.the.20th.century.runs.were.applied.directly.to.0.5˚.by.0.5˚.gridded.monthly.historic.climatology..the.advantage.of.this.approach.is.that.it.allows.investigation.of.all.the.iPcc.gcms.and.emissions.scenarios.at.the.native.spatial.resolution,.thereby.capturing.a.range.of.potential.climate.change.impacts.and.achieving.a.balance.between.precision.and.accuracy.
To reduce the uncertainties inherent in obtaining climate variables at high resolution, the 0.5˚ by 0.5˚ gridded data are ‘re-aggregated’ to the catchment level..the.average.scale.of.a.catchment.is.approximately.the.size.of.the.native.spatial.grid.scale.of.the.gcm.(~2.5˚.x.2.5˚).which.results.in.less.uncertainty.in.final.projections..Figure.5.2.shows.the.three.relevant.scales:.0.5˚.x.0.5˚.grid,.2.5˚.x.2.5˚.grid,.and.the.catchments..the.catchments.are.obtained.from.the.usgs.Hydro1k,.a.geographic.database..Hydro1k.has.six.levels.of.catchments..For.this.analysis.level.4.is.selected.for.all.bank.regions.except.AFr,.where.level.3.is.used..there.are.8,406.catchments.covering.the.world.bank.regions,.which.translate.into.an.average.of.six.0.5˚.x.0.5˚.grids.per.catchment..using.gis,.the.catchment.boundaries.are.overlaid.with.the.grids.and.the.cells.are.
Figure 5.1 The cone of uncertainty in scale and resolution of modeling
40
aggregated.by.their.weighted.area.in.the.catchment.
Generating and capturing climate change projections
In the context of downscaling, relying on results from a single or a few GCMs is not advisable..this.is.because.there.are.model.errors.in.any.one.model.and.natural.variability.(randomness).in.any.particular.run..A.single.model,.if.run.multiple.times.with.differing.initial.conditions,.can.provide.an.estimate.of.the.uncertainty.due.to.natural.variability..However,.for.any.given.model,.there.are.also.uncertainties.associated.with.the.assumptions.made.about.model.physics.and.parameterizations,.as.well.as.with.the.structural.aspects.of.the.model.itself..using.a.group.of.gcms.(multi-model.ensembles),.as.opposed.to.one.individual.gcm,.can.account.for.biases.and.errors..the.use.of.multi-model.ensembles.raises.the.question.of.how.to.capture.the.full.range.of.results.from.model.runs.
Strong caution is advised when using the mean of multiple models with the rationale that the mean is a good representation of all runs..this.can.lead.to.wrong.conclusions..the.problem.with.relying.on.the.mean.is.that.it.masks.extreme.values..A.model.‘average’.of.near.zero.could.be.the.result.of.models.predicting.near-zero.change,.but.also.the.result.of.two.opposing.changes.that.differ.in.sign,.as.seen.in.Figure.5.3..in.water.management,.it.is.in.the.‘tails’.of.the.full.spectrum.of.model.projections.where.the.risk.lies,.and.so.failing.to.capture.the.extremes.could.be.dangerous.
Potential exists for the range of model outcomes to vary so much that it could be construed as “noise”..However,.there.is.evidence.that.suggests.a.degree.of.consistency.in.some.of.the.more.salient.changes.generated.by.a.collection.of.model.outcomes..As.an.example,.the.trend.in.precipitation.intervals.as.simulated.by.the.iPcc.Ar4.models.show,.statistically.and/or.probabilistically.speaking,.agreement.in.the.projection.of.the.change.in.precipitation.interval.across.latitudes,.as.climate.warms..this.implies.that.although.one.should.not.rely.solely.on.a.single.model,.each.run.could.potentially.contain.important.information.that.is.more.than.merely.‘noise’..indeed,.there.are.regions.where.a.sign.change.is.consistent.amongst.the.climate.models—but.with.a.range.that.is.important.to.consider.explicitly.for.assessment.of.potential.impacts.
A related issue is filtering or screening of GCM and SRES scenarios that are implausible, or at the very least, extremely unlikely..this.is.difficult—if.not.impossible—to.unequivocally.
Figure 5.2 Section of the SAR region showing 0.5˚ by 0.5˚ grid scale, 2.5˚ by 2.5˚ (GCM) grid scale (dark larger grids), and catchment boundaries in color
85°0'0"E
85°0'0"E
82°30'0"E
82°30'0"E
80°0'0"E
80°0'0"E
67°30'0"E
67°30'0"E
77°30'0"E
77°30'0"E
75°0'0"E
75°0'0"E
72°30'0"E
72°30'0"E
70°0'0"E
70°0'0"E
32°30'0"N 32°30'0"N
30°0'0"N 30°0'0"N
27°30'0"N 27°30'0"N
25°0'0"N 25°0'0"N
22°30'0"N 22°30'0"N
20°0'0"N 20°0'0"N
17°30'0"N 17°30'0"N
15°0'0"N 15°0'0"N
12°30'0"N 12°30'0"N
10°0'0"N 10°0'0"N
7°30'0"N 7°30'0"N
41
determine.as.there.are.no.definitive.criteria.for.determining.whether.a.given.climate.change.projection.can.or.should.be.excluded..one.approach.in.impact.assessments.is.to.consider.all.modeled.projections.as.‘equally.likely’.at.the.outset.of.the.assessment,.and.then.to.exclude.in.a.secondary.step.those.scenarios.with.minimal.or.limited.impacts.(and.so.to.focus.on.those.that.could.cause.significant.damage/consequence)..techniques.are.being.developed.for.undertaking.a.full.probabilistic.analysis.of.scenarios.to.determine.which.are.most.applicable.to.each.region,.but.these.are.not.yet.available.for.practical.use.
In this analysis, the full spread of model projections—including extremes—is captured by identifying dry, medium and wet climate scenarios, as defined by a change in the climate moisture index (CMI).15.model.projections.are.not.screened..dry,.middle.and.wet.scenarios.are.identified,.specific.to.each.world.bank.region.(e.g.,.the.driest.scenario.for.lcr)..A.wet.scenario.means.that.the.location.experienced.the.smallest.impact.(or.change.in).cmi;.a.dry.scenario,.the.largest.impact;.and.a.medium.scenario,.an.impact.in.between.the.two.extremes..the.advantage.of.this.approach.is.that.it.provides.a.representation.of.the.full.range.of.available.scenarios.in.a.‘manageable’.way.(further.details.are.given.below).
analytical framework
Key hydrologic variables for water planning and management
A number of hydrologic variables or indicators have been proposed in the literature to assist policy-makers and planners in decision-making..themes.emerging.from.this.literature.suggest.a.set.of.indicators.that.provide.key.information.on.the.performance.of.water.resource.development.projects.in.the.near.future,.as.well.as.in.the.distant.future.under.the.threat.of.climate.
Figure 5.3 Range of relative change from historical climate for different GCMs. Mean is shown in heavy line
Source: giannini.et..al.,.2008.pg..376,.Fig..6.
15 Notethatemissions scenariosaredistinctfromclimate scenarios,whichareaplausibleandoftensimplifiedrepresentationofthefutureclimate.Climateprojections—theresponseoftheclimatesystemtoemissions/concentrationscenariosofgreenhousegassesandaerosols,orradiativeforcingscenarios,baseduponsimulationsbyclimatemodels—oftenserveastherawmaterialforconstructingclimatescenarios.Aclimate change scenarioisthedifferencebetweenaclimatescenarioandthecurrentclimate(Bates,etal,2008).
42
change..the.indicators.chosen.for.this.analysis.provide.information.on.mean and extreme values of runoff, the storage requirements for reliable basin yield, groundwater recharge, and net irrigation water demand.
SRES scenarios and GCMs
In this analysis, three SRES scenarios are used: B1, A1B, and A2..these.scenarios.are.chosen.because.they.are.included.in.the.marker.scenarios.identified.by.the.iPcc.and.are.in.the.middle.range.of.sres.scenarios.(Figure.5.4).16
There are 22 GCMs available via the IPCC 4th Assessment Report (AR4) to use in climate change analyses (Table 5.3)..in.this.analysis.all.of.the.gcms.are.evaluated.to.identify.dry,.medium.and.wet.projections.for.each.of.the.world.bank.regions.as.discussed.below.
Timeframe of analysis
Typical climate change analyses evaluate impacts anywhere from the 2030’s to the 2100’s..it.is.important.to.keep.in.mind.the.purpose.of.the.analysis,.i.e..near.term.planning.or.long.range.potential,.to.help.guide.which.future.decades.are.most.important.to.evaluate.for.investment.purposes..in.this.study.the.years.2030.and.2050.are.used.to.evaluate.the.impacts.of.climate.change.on.various.hydrologic.variables..these.years.are.chosen.for.two.reasons:.(i).this.is.the.relevant.timeframe.for.current.infrastructure.planning.and.(ii).beyond.2050.uncertainties.in.projections.increase.dramatically..As.shown.in.Figure.5.4,.sres.scenarios.are.tightly.bunched.until.2050,.at.which.time.they.start.to.diverge.significantly.
The years 2030 and 2050 here represent decadal averages of monthly GCM output..in.other.words,.when.reporting.changes.in.2030.relative.to.historical.climate,.these.are.actually.average.changes.from.2025.to.2035.relative.to.average.historical.climate..the.same.is.true.for.the.year.2050.(which.represents.the.average.from.2045.to.2055)..Average.monthly.changes.from.the.gcms.over.the.two.separate.decades.are.applied.to.historical.monthly.hydro-climatology.from.1961.to.1990.
Figure 5.4 Multi-model averages and assessed ranges for surface warming
Source: (iPcc.2007a,.pg14,.Figure.sPm.5.).solid.lines.are.multi-model.global.averages.of.surface.warming.(relative.to.1980–1999).for.the.scenarios.A2,.A1b.and.b1,.shown.as.continuations.of.the.20th.century.simulations.
16 Thereareatotalof40SRESscenarios,organizedintofourscenariofamilies(A1,A2,B1andB2).Markerscenariosrepresentagivenscenariofamily,althoughtheyarenotconsideredtobeanymore‘likely’thantheotherscenarios.ThesemarkerscenariosincludeA1B1,A2,B1,andB2,andtwoadditionalscenariosforthegroupsA1F1andA1T.
43
Application of Tools to Dialogues at National, River Basin and Project Level Analysis
The level of analysis reflected in this report is designed for use at the Country Assistance Strategy discussions, national water strategy planning and identification of investment potential at river basin scale..Projections.at.the.catchment.level.allow.for.analysis.of.inter-regional.variation.at.the.project.planning.scale..the.general.pattern.is.consistent.with.projections.of.runoff.made.directly.from.climate.model.runs..Here,.specific.indicators.provide.a.deeper.and.more.water.specific.insight.regarding.potential.changes.in.the.water.availability.and.distribution.for.various.uses.and.by.various.water.infrastructure.interventions..For.each.region,.detailed.information.for.each.of.these.indicators.is.available.at.the.0.5.x.0.5.degree.resolution,.as.well.as.aggregated.to.catchment.level..it.is.planned.that.this.information.will.be.made.available.via.a.web-based.interface.
Various hydrologic models can be used..the.hydrologic.model.used.for.this.study.clirun-ii.and.its.predecessors.have.been.used.extensively.since.1992.specifically.for.climate.change.analysis..while.there.are.a.number.of.global.hydrologic.models.that.could.be.used,.the.results.would.not.differ.significantly.since.they.solve.the.same.set.of.governing.equations..in.this.analysis.the.model.was.calibrated.and.validated.using.separate.historical.time.series.(see.below).
Prior to using the methodology at project level it is important to consider that the analysis is based on natural flows.and.does.not.take.into.account.specific.basin.development.and.structural.interventions..these.will.have.to.be.taken.into.consideration.for.detailed.project.design.and.risk.assessment..the.same.is.true.for.expected.changes.in.land.use.and.vegetation.which.impacts.on.the.hydrology.
Project specific design will have to continue to be done taking into account historical, local scale surface data..in.addition.down-scaling.from.the.local-scale.surface.weather.may.be.carried.out.using.the.technique.which.the.responsible.task.manager.in.each.case.deems.to.be.most.appropriate..Following.such.down-scaling.it.is.possible.to.project.hydrologic.variables.for.the.
Table 5.3 Available AR4 models, scenarios, and variables via IPCC
Models
bccr:. bcm2 mPim:. ecHAm5
cccmA:. cgcm3_1-t47 mri:. cgcm2_3_2
cccmA:. cgcm3_1-t63 nAsA:. giss-Aom
cnrm:. cm3 nAsA:. giss-eH
csiro:. mk3–5 nAsA:. giss-er
csiro:. mk3–0 ncAr:. ccsm3
gFdl:. cm2 ncAr:. Pcm
gFdl:. cm2_1 nies:. miroc3_2-Hi
inm:. cm3 nies:. miroc3_2-med
iPsl:. cm4 ukmo:. HAdcm3
lAsg:. FgoAls-g1_0 ukmo:. HAdgem1
44
investment.project.in.question..these.may.then.be.compared.to.projections.based.on.historical.data.only;.and.a.choice.will.have.to.be.made.with.regard.to.how.to.take.the.climate.change.based.projections.into.account..these.calculations.and.the.ensuing.design.will.be.carried.out.by.the.responsible.engineer.and.will.be.based.on.the.hydraulic.model.of.his.choice.and.the.design.parameters.and.safety.factors.which.he.deems.appropriate.in.the.light.of.the.project.and.local.regulations..A.key.value.of.the.approach.presented.in.this.report.is.that.it.provides.an.easy.to.use.database.which.can.provide.alternative.scenarios.as.background.for.the.project.analysis.to.be.undertaken.
Hydrologic drivers and data
Historical climate
The historical climate is taken from a database provided by the Climate Research Unit (CRU), University of East Anglia, Norwich, UK..the.cru.2.1.data.set.provides.a.time.series.of.monthly.precipitation.data.and.the.climate.variables.required.to.compute.potential.evapotranspiration.from.1901.to.2002..these.data,.provided.on.a.0.5˚.longitude/latitude.grid,.represent.the.world.meteorological.organization’s.(wmo).standard.reference.“baseline”.for.climate.change.impact.studies..the.climate.change.scenarios.(i.e..plausible.descriptions.of.how.things.may.change.in.future).are.expressed.as.changes.from.this.baseline..there.are.67,420.grids.(0.5˚.x.0.5˚).over.the.global.land.area,.excluding.Antarctica.
Historical observed runoff
Long-term average monthly runoff has been developed by the University of New Hampshire for the WMO Global Runoff Data Centre..the.“unH-grdc.composite.runoff.Fields.v1.0”.data.set.is.derived.from.observed.discharge.information,.using.a.climate-driven.water.balance.model..the.dataset.utilizes.a.gridded.river.network.at.0.5˚spatial.resolution.to.represent.the.riverine.flow.pathways.and.to.link.the.continental.land.mass.to.oceans.through.river.channels..the.data.set.provides.12.monthly.mean.values.and.a.mean.annual.value.of.runoff.for.over.50,000.grids.(0.5˚.x.0.5˚).over.the.global.land.area.excluding.permanent.ice.cover.such.as.much.of.greenland.and.all.of.Antarctica.
Historical indicators as baseline for future water investment assessment
Assessment of the impacts of climate change on water investments requires historical time series of runoff and projection of hydrologic drivers..An.observed.global.runoff.time.series.does.not.exist..the.disadvantage.of.the.unH-grdc.database.(discussed.above).is.that.the.discharge.is.gauged,.with.all.of.the.developments.implicit.in.the.measured.data..For.the.purposes.of.this.analysis,.a.new.dataset.based.on.natural.flows.has.been.developed..using.both.the.cru.Historical.climate.database.and.the.unH-grdc.composite.runoff.Fields.v1.0.database.as.input.to.the.global.runoff.model,.clirun-ii.(strzepek,.et.al,.2008),.30-year.monthly.time.series.of.runoff.at.the.50,000.plus.grids.of.the.unH-grdc.data.set.was.produced..the.time.series.uses.the.monthly.data.from.1961.to.1990.to.produce.a.historic.or.base.condition.against.which.the.projections.are.compared..clirun-ii.calibration.is.carried.out.using.the.cru.data.from.1961–1980.and.validation.was.performed.using.the.cru.data.from.1981–2002.
indicators.for.assessment.of.specific.water.services.and.water.management.investment.types.are.modeled.as.historic.baselines.(Figure.5.5)..these.indicators.are:.basin.runoff,.basin.yield,.10%.
45
and.90%.exceedance.probability.flows,.base.flow,.and.irrigation.demand.deficit..A.description.of.each.indicator.and.their.application.in.investment.types.is.provided.in.the.subsequent.sections..the.hydrologic.indicators.are.aggregated.to.“level.4.catchment”17.(approximately.2.x.2.degree.resolution).
Figure.5.6.shows.the.modeled.indicators.for.the.Africa.region.at.the.catchment.scale..the.entire.data.set.reflecting.the.historical.baseline.conditions.at.the.level.4.catchment.scale.is.now.available.for.all.bank.regions.upon.request.
Figure 5.5 Modeled historical baseline indicators at catchment scale for Bank regions (1961–1990). Units are in mm/yr.
17 ThecatchmentsareselectedfromtheUSGSHydro1KDrainageBasinDatabase.Level4catchmentdelineationhasanapproximateareaof2x2degree.Level4wasselectedinordertogaugethehydrologyresultstotheresolutionlevelofGCMclimateprojections.Thislevelalsolendsitselftowaterinvestmentsinriverbasins.
RunoffBasin Yield
Low Flow
Base Flow
Irrigation Deficit
High Flow
<10 10–100 100–500 500–1000 >1000
<10 10–100 100–500 500–1000 >1000
<10 10–100 100–500 500–1000 >1000
<10 10–100 100–500 500–1000 >1000
<10 10–100 100–500 500–1000 >1000
<10 10–100 100–500 500–1000 >1000
46
Figure 5.6 Modeled historical baseline indicators at catchment scale for Africa (1961–1990). Lines on the map delineate catchment boundaries. Units are in mm/yr.
< 50100 – 200400 – 80050 – 100200 – 400> 800
< 25125 – 250500 – 100025 – 125250 – 500> 1000
< 525 – 125250 – 5005 – 25125 – 250> 500
< 2040 – 80160 – 32020 – 4080 – 160> 320
< 525 – 50100 – 2005 – 2550 – 100> 200
< 500750 – 10001500 – 2000500 – 7501000 – 1500> 2000
Runoff
q90
q10
Basin yield
Base flow
Irrigation demand
47
Projections using Climate moisture index
The full spread of model results is captured by selecting the driest, the wettest, and middle climate projections..the.historical.model.simulations.and.all.22.gcm.projections.for.the.three.emissions.scenarios.are.analyzed.for.2030.and.2050..the.driest,.middle,.and.wettest.projections.are.identified.for.each.world.bank.region.(see.table.5.4.and.table.5.5)..the.projection.categorization.is.defined.by.the.climate.moisture.index.(cmi),.which.is.an.indicator.of.the.aridity.of.a.region..the.cmi.depends.on.average.annual.precipitation.and.average.annual.
Table 5.4. GCM and associated base CMIs used for each scenario and regions EAP, ECA, and LCR
Base
EAP ECA LCR
–0.069 –.205 –0.075
Model CMI Model CMI Model CMI
A2-dry csiro_mk3_5 –0.143 ipsl_cm4 –0.252 gfdl_cm2_0 –0.228
A2-middle mri_cgcm2_3_2a –0.082 ukmo_hadcm3 –0.215 ukmo_hadcm3 –0.151
A2-wet cccma_cgcm3_1_t63 –0.033 giss_model_e_r –0.177 cnrm_cm3 –0.068
A1b-dry csiro_mk3_5 –0.135 ipsl_cm4 –0.251 ukmo_hadgem1 –0.202
A1b-midde inmcm3_0 0.097 mpi_echam5 –0.212 mpi_echam5 –0.129
A1b-wet cccma_cgcm3_1 –0.054 cccma_cgcm3_1 –0.184 bccr_bcm2_0 –0.076
b1-dry csiro_mk3_5 –0.122 ipsl_cm4 –0.243 miroc3_2_hires –0.153
b1-middle mri_cgcm2_3_2a –0.084 mpi_echam5 –0.216 cccma_cgcm3_1 –0.11
b1-wet cccma_cgcm3_1_t63 –0.048 gfdl_cm2_1 –0.177 cnrm_cm3 –0.074
Table 5.5. GCM and associated base CMIs used for each scenario and regions MNA, SAR, and AFR
Base
MNA SAR AFR
–0.91 –0.372 –0.5
Model CMI Model CMI Model CMI
A2-dry gfdl_cm2_1 –0.942 ipsl_cm4 –0.466 inmcm3_0 –0.552
A2-middle ukmo_hadgem1 –0.920 ukmo_hadcm3 –0.312 mpi_echam5 –0.519
A2-wet ncar_pcm1 –0.898 mri_cgcm2_3_2a –0.055 ncar_ccsm3_0 –0.488
A1b-dry gfdl_cm2_1 –0.941 ipsl_cm4 –0.496 gfdl_cm2_1 –0.537
A1b-midde ukmo_hadcm3 –0.916 ukmo_hadgem1 –0.294 ukmo_hadgem1 –0.501
A1b-wet mpi_echam5 –0.891 mri_cgcm2_3_2a –0.003 cnrm_cm3 –0.484
b1-dry gfdl_cm2_1 –0.930 csiro_mk3_5 –0.433 ipsl_cm4 –0.539
b1-middle inmcm3_0 –0.907 inmcm3_0 –0.291 miroc3_2_medres –0.517
b1-wet mpi_echam5 –0.882 mri_cgcm2_3_2a –0.051 cnrm_cm3 –0.486
48
potential.evapotranspiration.(Pet).18.if.Pet.is.greater.than.precipitation,.the.climate.is.considered.to.be.dry.whereas.if.precipitation.is.greater.than.Pet,.the.climate.is.moist..calculated.as.cmi.=.(P/Pet)–1.{when.Pet>P}.and.cmi.=.1–(Pet/P).{when.P>Pet},.a.cmi.of.–1.is.very.arid.and.a.cmi.of.+1.is.very.humid..cmi.is.dimensionless.
Figure 5.7 shows the projected range of CMI for each scenario and each region of the World Bank for 2050..the.red.line.represents.the.median.cmi,.and.the.top.of.the.box.represents.the.25th.percentile.while.the.bottom.of.the.box.represents.the.75th.percentile..the.whiskers.show.the.extremes.and.the.cross-hairs.show.the.model.outliers..the.dashed.lines.represent.the.historical.cmi.(averaged.from.1960–1990)..For.example,.in.the.lcr.region,.there.is.a.75%.chance.of.drying.with.all.3.scenarios..the.cmi.for.the.sAr.region.has.the.largest.spread.because.of.the.way.the.different.gcms.model.the.monsoons..in.the.mnA.region,.there.is.little.variation.because.the.area.is.so.dry.
In this analysis the CMI is calculated over land masses only. many.climate.change.analyses.discuss.gcm.projections.over.land.and.sea,.but.for.hydrologic.impacts,.the.interest.in.cmi.is.over.land.only..moreover,.note.that.the.land-based.cmi.in.the.box.and.whiskers.plot.are.all.negative..Figure.5.8.shows.the.projected.range.of.cmi.for.bank.regions,.non-bank.regions.and.the.globe..note.that.the.land-based.cmi.projections.for.the.bank.regions.are.more.negative.than.non-bank.regions.(e.g.,.oecd)..However,.the.relative.aridity.(compared.with.the.historical).for.both.bank.and.non-bank.regions.remains.the.same.
Figure 5.7 Climate Moisture Index range for each climate scenario and each Bank region
CMI Historic and Range of 2050 Climate Change Impacts
–0.1
0
–0.2
–0.3
–0.4
–0.5
–0.6
–0.7
–0.8
–0.9
A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1 A2 A1b B1
EAP
ECALCR
SAR
MNA
AFR
LegendTop of box: 25th percentile Red line: median CMI Bottom of box: 75th percentileDashed line: historical CMI (1960–1990) Whiskers: extreme CMI values Cross hairs: model outliers
18 AverageannualPETisaparameterthatreflectstheamountofwaterlostviaevaporationortranspiration(waterconsumedbyvegetation)duringatypicalyearforagivenareaifsufficientwaterwereavailableatalltimes.Averageannualevapotranspiration(ET)isameasureoftheamountofwaterlosttotheatmospherefromthesurfaceofsoilsandplantsthroughthecombinedprocessesofevaporationandtranspirationduringtheyear(measuredinmm/yr).ET,whichisbothconnectedtoandlimitedbythephysicalenvironment,isameasurethatquantifiestheavailablewaterinaregion.PotentialevapotranspirationisacalculatedparameterthatrepresentsthemaximumrateofETpossibleforanareacompletelycoveredbyvegetationwithadequatemoistureavailableatalltimes.PETisdependentonseveralvariablesincludingtemperature,humidity,solarradiationandwindvelocity.Ifamplewaterisavailable,ETshouldbeequaltoPET.
49
runoff projections
A variety of approaches/models exist for generating runoff projections.19.in.this.analysis,.gcm.output.is.used.as.input.into.the.hydrologic.model.clirun-ii.(strzepek,.et.al,.2008)..this.model.was.developed.specifically.to.assess.the.impact.of.climate.change.on.runoff.and.to.address.extreme.events.at.the.annual.level.by.modeling.low.and.high.flows..this.analysis.advances.an.earlier.and.much.referenced.effort.by.milly,.et.al.(2005)..clirun-ii.is.an.“offline”.hydrologic.model.designed.for.application.in.water.resource.projects..milly.uses.runoff.estimates.derived.directly.from.approximately.2.5˚.x.2.5˚.gcm.precipitation.projections.and.reports.annual.runoff.at.5˚.x.5˚.resolution.with.some.degree.of.confidence..in.this.analysis,.runoff.is.projected.at.a.monthly.time.scale.at.a.resolution.0.5˚.x.0.5˚,using.clirun-ii..the.results.are.then.aggregated.to.about.2˚.x.2˚.for.a.higher.level.of.confidence.
table.5.6.provides.the.projected.percentage.change.in.runoff.at.catchment.scale.for.2030.and.2050.for.all.bank.regions..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet.projections..Projected.change.in.runoff.for.2030.is.mapped.for.all.bank.regions.and.presented.in.Figure.5.9..An.example.of.the.regional.distribution.of.change.in.runoff.for.the.Africa.region.is.provided.in.Figure.5.10.
basin yield projections
Annual runoff provides information on potential water resource availability, but not its accessibility which is a function of reservoir storage..basin.yield—which.is.directly.related.to.reservoir.storage—is.a.measure.of.the.firm.yield.and.reliability.of.water.supply.and.is.estimated.with.the.aid.of.a.‘storage.yield.curve’..A.storage.yield.curve.is.an.estimated.time.series.of.annual.
Figure 5.8 Climate Moisture Index range comparison of Bank and non-Bank regions
CMI Historic and Range of 2050 Climate Change Impacts
–0.18
–0.2
–0.22
–0.24
–0.26
–0.28
–0.3
–0.32
–0.34
A2 A1b B1 A2 A1b B1 A2 A1b B1
Globe
WB RegionsNon WB
LegendTop of box: 25th percentile Red line: median CMI Bottom of box: 75th percentileDashed line: historical CMI (1960–1990) Whiskers: extreme CMI values Cross hairs: model outliers
19 Thevariousapproachesarediscussedindetailinthecompanionreportonthescienceofwaterandclimatechange.
50
Figure 5.9 Projected percent change in runoff for 2030
or.monthly.flows.in.a.basin.and.is.used.to.provide.information.on.(i).the.storage.needed.to.provide.a.specific.amount.of.reliable.yield.and.(ii).for.any.given.storage,.the.reliable.yield.that.can.be.expected..difference.between.k.and.k’.is.storage.needed.to.compensate.for.basin.yield.loss.between.
Table 5.6 Summary changes in runoff projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry –5% –13% 5% –16% –17% –7%
medium 6% –4% 9% –3% –17% 26%
wet 30% 7% 13% 15% 24% 31%
2050 dry –13% –11% 8% –31% –50% –52%
medium 14% 3% 18% –9% –5% 20%
wet 31% 11% 18% 7% 31% 39%
A1b. 2030 dry –5% 7% 9% –9% –25% 18%
medium 3% 5% 13% –5% 12% 18%
wet –1% 11% 10% 9% 15% 43%
2050 dry –20% –12% 14% –25% –46% 24%
medium 0% –2% 21% –16% –16% 24%
wet 6% 21% 19% 7% 20% 37%
b1. 2030 dry –1% –8% 6% –13% –15% –20%
medium –9% 2% 11% –11% 12% –5%
wet 10% 14% 16% 11% 18% 36%
2050 dry –8% –8% 5% –9% –30% –14%
medium –12% –1% 14% –9% 19% 38%
wet 23% 15% 19% 9% 49% 33%
< –50 –20 to –10 0 to +10 20 to 50–50 to –20 –10 to 0 10 to 20 > +50
51
2005.and.2050.due.to.climate.change..the.maximum.yield.of.the.storage.yield.curve.is.generally.equivalent.to.the.average.annual.runoff.(ignoring.evaporation).and.the.minimum.yield.is.the.lowest.flow.in.the.time.series..climate.change.has.the.potential.to.impact.not.only.the.average.annual.runoff.in.a.basin,.but.also.the.variability.and.the.shape.of.the.storage.yield.curve.(Figure.5.11).
table.5.7.shows.the.percentage.change.in.basin.yield.at.a.catchment.level.in.the.years.2030.and.2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet.projections..Projected.change.in.basin.yield.for.2030.is.mapped.for.all.bank.regions.and.
Figure 5.10 Projected percent change in runoff for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
< –50 –19 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
52
presented.in.Figure.5.12..An.example.of.the.regional.distribution.of.change.in.runoff.for.the.Africa.region.is.provided.in.Figure.5.13.
extreme events projections
Annual runoff and basin yield provide information on average conditions, more is needed..it.is.in.the.‘extremes’.where.the.risks.of.climate.change.to.water.investments.and.planning.lie..this.assessment.is.one.of.the.first.attempts.to.develop.indicators—for.floods.and.droughts—based.on.time-series.rather.than.long-term.averages..As.compared.to.‘mean’.value.indicators,.indicators.of.extreme.events.carry.more.uncertainty.due.to.the.limited.data.at.the.tail.
Figure 5.11 Impact of climate change on reservoir yield and adaptations
Table 5.7 Summary changes in basin yield projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry 21% 42% –2% 44% 61% 40%
medium 9% 14% –9% 17% 60% –14%
wet –22% –7% –13% –10% –4% –22%
2050 dry 38% 42% –3% 74% 136% 53%
medium –2% 0% –14% 39% 24% –5%
wet –19% –13% –18% 5% 4% –29%
A1b. 2030 dry 26% –4% –9% 29% 85% –19%
medium 3% –2% –16% 26% –17% –19%
wet 7% –12% –7% –1% –11% –29%
2050 dry 53% 49% –12% 57% 141% –18%
medium 12% 10% –24% 53% 55% –18%
wet –4% –25% –21% 6% –19% –32%
b1. 2030 dry 8% 35% –2% 38% 46% 45%
medium 27% 1% –15% 35% 13% 27%
wet –5% –17% –15% –6% –7% –26%
2050 dry 30% 26% 4% 27% 103% 30%
medium 37% 7% –16% 30% 26% –31%
wet –14% –20% –21% –5% –29% –28%
53
Figure 5.12 Projected percent change in basin yield for 2030
Figure 5.13 Projected percent change in basin yield for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
< –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
< –50 –19 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
54
of.the.probability.distribution..However,.it.is.useful.to.have.some.indication.of.extreme.events,.even.while.bearing.this.additional.uncertainty.in.mind.
Drought and flood indicators are estimated based on flow frequency analysis.
•.drought.indicator:.this.indicator.is.taken.as.the.flow.that.is.exceeded.90%.of.the.time.(q90),.which.means.there.is.a.10%.chance.in.each.time.period.of.a.flow.lower.than.this..A.decrease.in.q90.means.that.the.likelihood.of.low.flows.and.droughts.will.increase.
•.Flood.indicator:.this.indicator.is.taken.as.the.flow.that.is.exceeded.10%.of.the.time.(q10),.which.means.there.is.a.90%.chance.in.each.time.period.of.a.flow.lower.than.this..An.increase.in.q10.means.that.the.likelihood.of.high.flows.and.floods.will.increase.
the.relative.changes.in.the.q90.and.q10.from.the.historical.values.will.provide.an.“indication”.of.the.projected.changes.in.droughts.and.floods.
table.5.8.and.table.5.9.show.the.percentage.change.in.q90.and.q10,.respectively,.at.a.catchment.level.for.2030.and.2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet.projections..Projected.changes.in.drought.and.flood.for.2030.are.mapped.for.all.bank.regions.and.presented.in.Figure.5.14.and.Figure.5.15..An.example.of.the.regional.distribution.of.change.in.floods.and.droughts.for.the.Africa.region.is.provided.in.Figure.5.16.and.Figure.5.17.
Table 5.8 Summary changes in low flow projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry –4% –14% 7% –18% –19% –5%
medium 6% –4% 10% –2% –18% 31%
wet 37% 8% 14% 19% 18% 31%
2050 dry –15% –11% 10% –35% –52% –55%
medium 19% 3% 21% –11% –8% 21%
wet 40% 13% 19% 9% 17% 41%
A1b. 2030 dry –5% 7% 11% –11% –29% 20%
medium 3% 5% 15% –5% 9% 20%
wet –1% 12% 10% 9% 13% 47%
2050 dry –23% –13% 18% –32% –50% 25%
medium 0% –2% 23% –18% –24% 25%
wet 7% 21% 19% 8% 3% 40%
b1. 2030 dry 0% –9% 9% –17% –19% –22%
medium –12% 2% 13% –15% 9% –3%
wet 13% 14% 17% 10% 12% 37%
2050 dry –8% –9% 7% –13% –34% –17%
medium –14% –1% 17% –13% 8% 48%
wet 30% 14% 20% 9% 37% 37%
55
Figure 5.14 Projected percent change in low flows (drought) for 2030
Table 5.9 Summary changes in high flow projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry –4% –13% 5% –16% –15% –8%
medium 5% –3% 8% –2% –16% 23%
wet 27% 7% 13% 14% 25% 32%
2050 dry –11% –10% 7% –28% –48% –50%
medium 13% 3% 17% –9% –4% 21%
wet 27% 11% 17% 7% 36% 39%
A1b. 2030 dry –4% 7% 8% –8% –24% 18%
medium 3% 5% 13% –4% 10% 18%
wet –1% 10% 10% 9% 13% 43%
2050 dry –18% –12% 12% –21% –43% 24%
medium 1% –2% 20% –14% –13% 24%
wet 6% 20% 19% 7% 27% 35%
b1. 2030 dry –1% –8% 6% –11% –13% –18%
medium –7% 2% 10% –9% 12% –5%
wet 9% 13% 17% 11% 22% 36%
2050 dry –7% –8% 4% –7% –26% –12%
medium –10% –1% 13% –7% 20% 34%
wet 20% 15% 19% 8% 52% 32%
< –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
56
Figure 5.15 Projected percent change in high flows (floods) for 2030
Figure 5.16 Projected percent change in low flows (drought) for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
< –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
< –50 –19 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
57
base flow projections
Much of water resources development, particularly rural water supply and small scale irrigation, is dependent on groundwater resources..it.is.important.to.provide.an.indicator.of.the.impact.of.climate.change.on.local.groundwater.resources..modeling.of.the.global.groundwater.system.is.highly.complex.and.well.beyond.the.scope.of.this.analysis..However,.a.screening.level.proxy.indicator—base.flow—can.provide.important.information,.and.provide.some.indication.of.the.water.available.in.the.basin.(deep.groundwater.excluded).for.basin.management.interventions.and.conjunctive.water.use..For.each.catchment,.the.30-year.monthly.time.series.is.analyzed.for.estimation.of.the.base.flow.as.the.contribution.of.shallow.groundwater.to.the.runoff.
table.5.10.shows.the.percentage.change.in.base.flow.at.catchment.level.for.2030.and.2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet.projections..Projected.change.in.base.flow.for.2030.is.mapped.for.all.bank.regions.and.presented.in.Figure.5.18..An.example.of.the.regional.distribution.of.change.in.base.flow.for.the.Africa.region.is.provided.in.Figure.5.19.
Figure 5.17 Projected percent change in high flows (floods) for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
< –50 –19 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
58
Table 5.10 Summary changes in base flow projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry –14% –32% 21% –24% –7% –14%
medium –7% –13% 12% –7% –19% 33%
wet 27% 6% 19% 17% 4% 32%
2050 dry –12% –30% 26% –37% –51% –44%
medium –8% –6% 33% –18% –9% 25%
wet 12% 10% 33% 21% 58% 35%
A1b. 2030 dry –9% 2% 20% –11% –30% 27%
medium 5% 2% 24% –10% 4% 27%
wet 0% 9% 23% 16% 5% 47%
2050 dry –17% –34% 33% –33% –57% 27%
medium –3% –12% 40% –19% –17% 27%
wet 13% 35% 29% 8% 17% 37%
b1. 2030 dry –4% –19% 19% –14% –18% –10%
medium –10% –2% 6% –6% –13% –16%
wet 8% 23% 20% 21% 15% 28%
2050 dry –14% –21% 18% –14% –39% –5%
medium –13% –13% 33% –2% 12% 24%
wet 10% 21% 23% 2% 87% 29%
Figure 5.18 Projected percent change in base flow for 2030
< –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
59
net irrigation demand projections
Irrigation is a major user of water and could be significantly impacted by climate change..detailed.crop.modeling.at.the.global.grid.scale.is.well.beyond.the.scope.of.this.analysis,.but.‘simpler’.methods.can.provide.important.information.on.net.irrigation.demand.at.a.broader.scale..water.deficit.index.(wdi).can.be.used.as.an.indicator.of.irrigation.performance..the.wdi.has.recently.been.developed.for.the.reference.crop,.grass,.as.a.generic.index.for.quantifying.crop.water.stress.for.various.crops..this.simple.method.has.been.employed.for.climate.change.analyses.at.local.and.regional.levels.
the.water.deficit.index.(wdi).is.an.estimate.of.the.difference.between.precipitation.and.crop.water.requirements,.on.a.monthly.time.scale:
wdi.=.∑.(cwr.–.Precip)..t.if.cwr.t.–.Precip.t.>.0.else.0
where,cwr.=.kc(t).*.Pet(t)kc.=.crop.factor.(crop.per.drop)Pet.=.Potential.evapotranspiration
Figure 5.19 Projected percent change in base flow for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
–100 to –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 +50 to +200
60
wdi.assumes.a.reference.perennial.grass.crop.factor,.kc,.which.has.a.value.of.one..the.modified.Hargreaves.methodology.is.used.for.calculating.Pet..Pet.data.are.consistent.with.what.is.used.in.the.runoff.and.basin.yield.analysis.(refer.above.discussion).and.clirun-ii.model..the.calculation.of.the.cwr.is.performed.at.the.gridded.scale.and.aggregated.to.the.catchment.and.regional.levels.
table.5.11.shows.the.percentage.change.in.water.deficit.index.at.catchment.level.for.2030.and.2050..the.results.are.reported.for.three.sres.scenarios.and.for.the.identified.dry,.medium.(middle).and.wet.projections..Projected.change.in.water.deficit.index.for.2030.is.mapped.for.all.bank.regions.and.presented.in.Figure.5.20..An.example.of.the.regional.distribution.of.change.in.water.deficit.index.for.the.Africa.region.is.provided.in.Figure.5.21.
Table 5.11 Summary changes in water deficit index projections for Bank regions
SRES
Scenario Year Projection AFR EAP ECA LCR MNA SAR
A2. 2030 dry 0% 122% 10% 40% –5% 9%
medium –1% 91% –15% 30% –1% –6%
wet –10% 70% –18% 12% –4% –10%
2050 dry –2% 127% 17% 69% 6% 26%
medium 4% 87% –16% 37% 0% –3%
wet 5% 74% –16% 21% –12% –5%
A1b. 2030 dry 13% 106% 30% 59% 14% 33%
medium 13% 97% 19% 59% 7% 4%
wet 10% 90% 19% 25% 7% 3%
2050 dry 29% 141% 44% 87% 23% 33%
medium 18% 114% 28% 64% 15% 4%
wet 5% 65% 19% 39% 11% 11%
b1. 2030 dry 15% 125% 35% 41% 10% 23%
medium 16% 104% 9% 23% 10% 22%
wet 9% 71% 6% 13% 8% 5%
2050 dry 20% 132% 44% 48% 14% 17%
medium 18% 117% 25% 22% 8% 12%
wet 16% 67% 5% 44% –5% 10%
61
Figure 5.20 Projected percent change in water deficit index for 2030
Figure 5.21 Projected percent change in water deficit index for 2030 at catchment level – Africa Region. Catchment boundaries are not delineated
< –50 –20 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
< –50 –19 to –5 0 to +5 +20 to +50–50 to –20 –5 to 0 +5 to +20 > +50
62
63
CHaPTer 6: ClimaTe CHange and THe world bank waTer PorTfolio
introduction
climate.change.poses.risk.to.world.bank.investments.in.the.water.sector..in.order.to.understand.the.magnitude.of.water.challenges.and.the.exposure.of.bank’s.investments.to.climate.change,.a.detailed.analysis.of.the.water.portfolio.was.conducted..this.chapter.attempts.to.review.bank’s.investments.in.the.water.sector.over.the.period.fiscal.year.2006–2010.and.establish.potential.linkages.to.climate.variability.and.change..more.specifically,.the.objective.of.this.chapter.is.to.assess.the.exposure.of.bank’s.water.investment.to.current.hydrologic.variability.and.future.climate.change..to.this.end,.this.chapter.covers.the.following:
•.Assess.the.world.bank’s.current.portfolio.and.pipeline.in.the.water.sector,.identifying.the.financing.directed.to.the.different.water.systems.(services.and.resources).
•.Analyze.the.extent.in.which.bank.projects.adopt.measures.with.respect.to.climate.variability.or.climate.change.at.the.project.design.level..the.focus.is.on.adaptation,.but.projects.with.mitigation.measures.were.also.identified.
•.identify.the.exposure.of.bank’s.investments.to.the.hydrologic.aspect.of.climate.change.
framework for analysis
Classification of water systems used for the 2003 Water Resources Sector Strategy is adopted here..this.allows.the.project.lending.information.to.be.disaggregated.into.different.water.systems..A.single.project.may.have.one.or.more.water.systems.assigned.to.it..this.level.of.detail.is.not.available.in.the.bank’s.institutional.database,.thus.the.reason.for.this.comprehensive.review..by.definition,.a.“system”.includes.all.elements.and.components.that.make.it.perform.its.intended.function.under.a.defined.set.of.conditions..this.includes.hardware,.software,.institutions,.and.more..For.the.purposes.of.this.review.and.clarity,.the.definitions.provided.here.are.divided.into.the.physical.(infrastructure).and.institutions.(all.other.aspects).parts..this.will.allow.addressing.the.climate.impact.and.vulnerability.for.each.aspect.separately.while.recognizing.that.the.infrastructure.and.institutional.aspects.of.a.system.are.inseparable.
The investments in the water sector are divided into two major categories/systems: those that help deliver services and those that manage the resource..Figure.6.1.shows.the.classification.of.water.systems.used.in.this.review..the.reason.for.this.categorization.is.that.impact.of.climate.change.on.services.delivery.systems.is.expected.to.be.different.from.systems.designed.for.management.of.the.resources..the.same.is.true.for.adaptation.options.that.may.be.selected..naturally,.the.exposure.to.climate.change.and.the.need.for.adaptation.are.more.pronounced.the.longer.the.lifetime.of.the.infrastructure.
The Project Appraisal Document (PAD) was reviewed in detail for each project in order to identify the different water systems and allocate the costs to each system..when.the.PAd.was.not.available.(which.was.the.case.in.some.pipeline.projects),.the.Project.information.document.(Pid).or.the.integrated.safeguard.data.sheet.was.used.for.cost.allocation..in.order.to.ensure.consistency.with.the.total.lending.of.the.sector,.the.total.lending.allocated.to.each.water.system,.with.exception.of.multi-purpose.facilities,.did.not.exceed.that.reported.by.the.bank’s.institutional.database..since.multi-purpose.facilities.(e.g..dams,.hydropower).are.not.captured.
64
automatically.in.the.bank’s.institutional.database,.additional.lending.was.allocated.to.the.total.water.lending..For.projects.in.the.pipeline.with.limited.information,.the.project’s.file.(in.the.operations.Portal).was.examined.to.obtain.more.information.about.the.project..in.some.cases,.the.project.task.manager.was.contacted.for.additional.information.
The global water challenges bring increasing demands for World Bank engagement in developing countries..in.2003,.the.board.of.directors.of.the.bank.approved.a.water.resources.sector.strategy.which.delivered.several.key.messages.regarding.the.sector..As.part.of.this.strategy,.an.assessment.of.the.world.bank.water.portfolio.was.conducted.to.understand.the.magnitude.of.bank.investments.in.the.water.sector..the.assessment.showed.that.the.composition.and.value.of.water.investments.in.the.bank.are.very.diverse.with.wide.regional.variations.in.the.patterns.of.lending.for.water-related.projects..Following.the.first.assessment.of.the.bank’s.water.portfolio,.a.similar.review.of.the.bank’s.investments.in.water.over.the.period.Fy06–10.is.made.with.focus.on.potential.linkages.to.climate.variability.and.change..the.objective.of.this.assessment.is.to.determine.the.extent.to.which.the.bank’s.water.portfolio.is.exposed.to.hydrologic.variability.and.change,.and.whether.potential.actions.to.mitigate.the.negative.impacts.have.been.considered.in.project.design.
Content of the water portfolio
The composition of the World Bank investments in water is very diverse with wide regional variations in the lending for water projects..For.the.Fy06–08.period,.water.investments.were.committed.in.83.countries.across.the.six.regions.of.the.bank.(Figure.6.2.and.Figure.6.3).
The World Bank’s water portfolio selected for this review consists of 191 active projects approved in FY06–08 with total net commitments of $8.8 billion..For.approvals.in.Fy06–08,.the.water.lending.represents.11%.of.the.total.world.bank’s.investments.(Figure.6.4)..the.regions.that.invested.the.most.in.water.relative.to.their.total.wb.regional.investment.are.mnA.(14%).and.sAr.(14%).and.the.region.that.invested.the.least.is.lcr.(8%)..on.a.yearly.basis,.the.share.of.water.
Figure 6.1 Classification of water systems
Irrigation and Drainage
Water Services
Water Projects
Water Resources
Urban Water and Sanitation
Rural Water and Sanitation
Flood Control
Water Resources Management
Watershed Management
Multi-purpose facilities
65
lending.relative.to.the.overall.world.bank’s.investments.has.increased.from.8%.in.Fy06.to.12%.in.Fy08..yearly.average.water.lending.for.the.Fy06–08.period.amounts.to.$2.9.billion..A.pipeline.of.projects.with.expected.approvals.in.Fy09–10.consists.of.220.projects.corresponding.to.a.volume.of.us$11.3.billion20.(Figure.6.5).
20 Pipelineresultsshouldbeconsideredwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure 6.2 Location of World Bank water projects for FY06–08 (active) and FY09–10 (pipeline)
Figure 6.3 World Bank water lending volume (shading) and class (bar) for FY06–08
66
AFR region has led the lending in water with a total of $2 billion for the past three fiscal years (24% of Bank’s overall water investments) consisting of 52 active projects..the.second.largest.share.of.water.commitments.is.in.sAr.(23%).corresponding.to.28.projects,.followed.by.eAP.(19%),.ecA.(14%).and.lcr.(13%)..mnA.region.accounts.for.the.smallest.share.both.in.terms.of.investments.(7%).and.number.of.projects.(8%).as.shown.in.Figure.6.6.
The water portfolio continues to be dominated by projects that primarily deliver water services (Figure.6.7)..For.the.Fy06–08.period.lending.for.water.services.prevails.over.water.management.not.only.in.volume.(70%).but.also.in.number.of.projects.(63%)..it.is.important.to.note.that.investments.towards.water.services.exceed.investments.in.water.resources.for.all.bank.regions..For.the.active.period,.a.good.portion.of.the.lending.in.water.resources,.is.going.to.AFr.($926.million),.followed.by.sAr.($703.million).and.eAP.($364.million).regions..in.terms.of.project.number,.there.is.a.similar.trend.with.AFr.accounting.for.the.largest.share.(26%).of.water.resources.systems..similar.to.water.resources,.the.three.regions.with.the.largest.investment.in.water.services.systems.are.eAP.($1,327.million),.sAr.($1,241.million).and.AFr.regions.($1,128.million)..in.terms.of.number.of.projects,.lcr.(24%).leads.with.the.most.number.of.projects.with.water.services.systems.closely.followed.by.AFr.(23%).
Urban water supply and sanitation active projects account for almost half of the total investments (45%) for the FY06–08 period..this.pattern.is.seen.in.all.regions,.except.for.sAr,.where.irrigation.and.drainage.systems.dominate.investment.in.the.region..the.second.largest.share.of.investments.is.in.multi-purpose.facilities.(17%).followed.by.irrigation.and.drainage.(16%),.and.rural.water.and.sanitation.(10%)..A.small.percentage.of.the.total.commitments.are.directed.towards.other.water.systems.such.as.flood.control.(6%),.water.resources.management.(6%),.and.watershed.management.(1%)..it.is.of.relevance.to.mention.that.most.of.investments.in.multi-purpose.systems.
Figure 6.4 Water lending as a share of overall regional lending in the FY06–08
20
15
10
5
0AFR EAP ECA LCR MNA SAR Bank-
wide
Wa
ter L
en
din
g S
ha
re (
%)
Figure 6.5 World Bank’s water lending and number of projects for FY06–08 and FY09–10
12
10
8
6
4
2
0
200
150
100
50
0AFR EAP ECA LCR MNA SAR Total
US$
bill
ion
No
. of P
roje
cts
67
in.the.Fy06–08.period.are.in.AFr.(48%).and.sAr.(38%),.and.most.of.the.investments.in.irrigation.and.drainage,.and.rural.water.are.in.sAr.(49%.and.31%.respectively).
The pipeline21 follows a similar pattern with regards to distribution of lending by water systems. Projects involving delivery of water services are expected to constitute nearly 70% of the total lending in the pipeline..Following.the.historical.trend,.urban.water.supply.and.sanitation.systems.are.expected.to.lead.in.terms.of.lending.volume.(48%).while.irrigation.and.drainage.and.multi-purpose.facilities.are.also.expected.to.account.for.a.considerable.portion.of.the.pipeline.(16%.and.13%.respectively)..the.pipeline.shows.growth.in.investments,.with.the.average.yearly.lending.expected.to.almost.double.compared.to.the.Fy06–08.period..most.regions.are.projected.to.have.an.increase.in.water.investments,.notably.the.lcr,.eAP.and.sAr.regions..Although.AFr.is.showing.a.small.percentage.decrease.in.terms.of.water.investments.(yearly.average).for.Fy09–10,.there.is.a.considerable.increase.in.terms.of.number.of.projects.per.year..the.largest.share.of.projects.in.the.pipeline.is.in.AFr.(25%),.followed.by.lcr.(23%).and.eAP.(19%).regions.
Climate change content of the portfolio
Adaptation to climate change in the portfolio
The portfolio and the pipeline were reviewed to determine whether hydrologic variability and climate change actions are considered and if so, to what degree incorporated into
21 Pipelineresultsshouldbeconsideredwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure 6.6 Regional distribution of the World Bank water lending for the FY06–08
SAR23%
AFR24%
ECA14%
LCR13%
MNA7%
EAP19%
Figure 6.7 Lending distribution in water services and water resources for the FY06–08
SAR20%
SAR27%
AFR18%
AFR35%
ECA15%
ECA12%
LCR15%
LCR9%MNA
9%
Water Services FY06–FY08 Water Resources
Water Services$6,153m
(70%)
WaterResources$2,620m
(30%)
MNA3%
EAP23%
EAP14%
68
the design of projects..this.review.does.not.attempt.to.assess.the.efficacy.of.those.interventions,.but.rather,.attempts.to.give.a.general.idea.of.whether.climate.change.is.reflected.in.the.current.and.future.portfolio.of.the.water.sector..climate.interventions.are.identified.and.distinguished.between.mitigation.and.adaptation.measures..Adaptation.is.further.classified.in.two.broad.categories—‘no.regret’.and.‘climate-justified’,.and.further.grouped.into.several.areas.of.intervention.
Review of the portfolio suggests an increasing level of attention to climate change. the.review.of.water.projects.for.inclusion.of.mitigation.and.adaptation.measures.yielded.the.following.results..of.191.active.projects.approved.in.Fy06–08,.35%.(67.projects).considered.strategies.to.reduce.the.impacts.of.climate.variability.and.change,.including.adaptation.and/or.mitigation.measures..of.the.67.projects.with.some.strategy,.58%.are.related.to.adaptation,.31%.related.to.mitigation.and.10%.related.to.both.
Water sector projects are primarily focused on adaptation..For.the.active.portfolio,.20%.of.the.projects.addressed.climate.variability.and.change.through.adaptation.measures..on.average,.there.were.13.projects.with.potential.adaptation.actions.each.year.for.the.Fy06–08.period,.with.a.promising.growth.expected.for.the.Fy09–10.period..of.the.20%.of.projects.taking.adaptation.measures,.it.is.important.to.note.that.these.measures.address,.for.the.most.part,.strategies.to.reduce.vulnerability.to.climate.variability.more.than.looking.at.the.long-term.effects.of.climate.change..of.the.total.number.of.projects.at.the.regional.level,.lcr.had.the.largest.portfolio.with.adaptation.measures.(28%).followed.by.sAr.(25%).and.mnA.(25%).(Figure.6.8)..the.pipeline.shows.an.increased.attention.to.the.adaptation.agenda.for.most.regions,.with.mnA.and.eAP.in.the.forefront.in.terms.of.considering.adaptation.measures.in.their.overall.pipeline.of.projects..Although.mnA.shows.a.high.percentage.of.adaptation.measures.in.the.active.portfolio.and.pipeline,.the.total.number.of.projects.(with.and.without.adaptation).is.very.low.compared.to.other.regions..overall,.there.is.clearly.a.higher.level.of.awareness.among.the.bank.and.client.countries.towards.climate.change.and.climate.variability.issues..note.that.the.pipeline.results.should.be.viewed.with.caution.as.there.is.some.degree.of.volatility.with.regards.to.approval.dates,.commitment.amounts,.etc.
The mitigation agenda is more visible in the energy sector than the water sector, but increasing attention is given to how the sector can contribute to the reduction of greenhouse gases..of.the.total.active.portfolio,.11%.of.the.actions.were.aiming.at.reducing.greenhouse.gas.emissions..only.projects.in.which.the.role.of.low.carbon.technology,.as.well.as.the.reduction.of.greenhouse.gas.emissions,.are.explicitly.mentioned.in.the.documents.are.classified.here.as.mitigation.projects..many.mitigation.strategies.are.also.linked.to.adaptation,.such.as.the.case.of.some.hydropower.projects..some.examples.of.mitigation.measures.
Figure 6.8 Projects with potential adaptation measures (%)
10
20
30
40
50
0AFR EAP ECA LCR MNA SAR Bank-
wide
% W
ate
r pro
jec
ts
FY06–08 (Active) FY09–10 (Pipeline)
69
identified.are.improvement.of.energy.efficiency.of.water.supply.systems.(e.g..replacing.pumps),.wastewater.treatment.technologies.to.reduce.methane.emissions,.mangrove.carbon.sequestration,.methane.collection.in.anaerobic.lagoons,.restoration.of.natural.drainage.regime.for.carbon.sequestration,.and.so.on..the.reduction.of.carbon.emissions.in.these.projects.is.for.the.most.part.linked.to.carbon.finance.investments,.which.is.a.strong.business.at.the.bank.
The portfolio shows two broad categories of actions: ‘no regret’ and ‘climate justified’..many.of.the.actions.to.reduce.vulnerability.to.climate.variability.are.no.different.in.a.world.with.climate.change.than.they.are.in.a.world.without.it..these.actions.are.called.‘no.regret’.and.some.examples.include.reform,.institutional.and.infrastructure.measure.to.increase.water.use.efficiency.and.productivity,.such.as.water-conserving.irrigation.technologies;.increased.water.availability.through.storage.and.better.management.of.bulk.water;.wastewater.recycling;.economic.incentives,.including.pricing;.and.the.encouragement.of.water.markets.that.move.water.to.high-valued.uses..these.options.carry.‘no.regrets’.in.that.they.would.go.a.long.way.in.confronting.the.climate.change.challenges,.yet.they.are.by.definition.justifiable.even.under.expected.climatic.conditions.without.anthropogenic.climate.change..on.the.other.hand,.other.actions.might.be.justifiable.under.conditions.of.anthropogenic.climate.change..‘climate-justified’.actions.include.those.taken.solely.for.the.purpose.of.adapting.or.coping.with.such.impacts..those.typically.include.constructing.new.infrastructure.(dams,.underground.storage,.irrigation.systems),.retrofitting.existing.infrastructure,.changing.rules.of.operation,.tapping.new.sources.of.water,.water.transfers,.conjunctive.use.of.surface.and.groundwater,.innovative.demand.management,.etc..it.should.be.noted.that.some.of.these.action.types.may.be.“no.regret”.in.one.set.of.circumstances.and.“climate.justified”.in.another.
The review shows strong emphasis on ‘no regret’ actions, with 67% of the adaptation projects adopting measures that meet current economic, social and environmental objectives but also serve the dual purpose of reducing vulnerability to climate change..At.the.regional.perspective,.most.of.the.‘no.regret’.actions.are.in.AFr.and.lcr..the.pipeline.follows.the.same.pattern,.with.‘no.regret’.actions.prevailing.over.‘climate-justified’,.and.showing.a.distribution.of.actions.prevailing.in.AFr,.eAP.and.lcr.
‘Climate-justified’ actions are less predominant in the portfolio, representing 33% of the adaptation projects, or 8% of all active projects..For.the.Fy06–08.period,.most.of.these.actions.were.concentrated.in.lcr.and.eAP..examples.of.actions.include—mainstreaming.climate.change.considerations.in.public.policy;.institutional.consolidation.of.flood.control.for.a.medium.and.long-term.intervention.strategy.(to.help.the.country.adapt.to.sea.level.rise);.implementation.of.pilot.adaptation.measures.for.wetland.restoration.strategies,.implementation.of.climate.resilient.measures.such.as.rainwater.harvesting,.creating.better.capacity.and.awareness.among.farmers.for.adoption.of.new.techniques.for.coping.with.the.effects.of.climate.change;.among.others..the.pipeline.shows.a.larger.percentage.of.projects.with.‘climate-justified’.measures,.most.of.which.are.in.lcr,.sAr,.and.eAP.
Types of Adaptation Interventions as Identified in the Portfolio
Building resilience to current climate variability or adapting to future climate change will require interventions in several areas..some.of.the.overarching.areas22.highlighted.in.this.review.are:.policy/institutions,.management/operations,.infrastructure,.technology/innovation,.
22 Categoriesidentifiedfromabroadrangeofspecificactionstofacilitatepresentationandutilizationofreport.Theseareconsistentcategoriesfoundinpublicliterature.Thesecategoriesarenotexhaustive.
70
capacity.building/awareness.and.monitoring/information.systems.(Figure.6.9)..to.increase.water.security.stronger.institutions.are.needed,.as.well.as.more.investments.in.infrastructure.(small.and.large),.and.new.technologies.for.increasing.water.use.efficiency..moreover,.better.water.management.and.operations,.coupled.with.stakeholders.capacity.building.and.enhanced.monitoring.and.information.systems,.are.also.essential.elements.for.adapting.to.climate.change.
For the active and the pipeline23 periods, policy/institution interventions dominate with 27% and 33% of the adaptation actions respectively (Figure 6.10)..Projects.with.these.interventions.are.mostly.concentrated.in.AFr,.lcr.and.sAr.for.the.active.period..these.involve.institutional.strengthening.and.capacity.for.multi-sectoral.planning,.development.and.management.of.water.resources..more.specifically,.these.actions.support.policy,.legal.and.regulatory.environment.for.the.efficient.and.sustainable.management.of.water.resources..in.some.cases,.the.institutional.interventions.are.more.specific.to.climate.as.to.developing.climate.change.policy.or.adaptation.strategies..Having.strong.institutions.with.the.right.institutional.framework.is.a.first.step.towards.adapting.to.changes.in.climate.
Specific examples of adaptation options in the portfolio with policy/institution intervention are listed below without any particular preference on ranking:
•.consolidate.and.improve.water.resource.management.and.policy.through.institutional.strengthening.and.improved.planning,.regulation.and.financing.instruments.
•.strengthen.the.institutional.and.policy.development.capacity.of.the.water.agency.within.an.integrated.water.resources.management.framework.by.preparing,.enhancing.and.implementing.water.basin.plans.
•.improve.institutional.capacity.for.basin-scale,.participatory,.integrated.wrm.for.the.newly.created.national.water.Authority,.and.formulate.a.national.strategy.for.water.quality.management.
•.strengthen.institutional.capacity.for.managing.shared.trans-boundary.natural.resources.•.institutional.consolidation.of.flood.control.to.create.a.consensus.around.a.medium.and.long.
term.intervention.strategy.to.adapt.to.sea.level.rises.•.strengthen.institutional.capacities.to.reduce.vulnerability.to.the.natural.and.manmade.hazards.
and.to.limit.losses.due.to.disasters.•.mainstream.climate.change.considerations.in.public.policy.as.part.of.the.national.climate.
change.strategy.
Interventions related to management/operations are the second highest share for both periods, with AFR, ECA and LCR in the forefront in terms of adopting management
23 Thepipelineresultsshouldbeconsideredwithcautionandviewedasillustrative,astherearemanyprojectsforwhichdocumentswerenotavailableinthesystem.
Figure 6.9 Types of climate change interventions
Technology
Type of Intervention
Monitoring/Informationsystems
Capacity buildingawareness
Policy/Institution
Water Management
Infrastructure
71
instruments or tools for the effective operation and management of water systems..more.specifically,.projects.with.these.actions.include.implementation.of.economic.incentives.such.as.water.markets,.water.pricing;.conjunctive.management.of.groundwater.and.surface.water;.watershed.and.flood.management.planning,.etc..A.wide.range.of.demand-side/supply-side.management.measures.are.considered.which.will.help.address.the.quality.and.availability.of.water.resources,.its.efficient.and.equitable.allocation.to.the.various.end-users,.and.help.reduce.the.vulnerability.to.extreme.climatic.events.and.long-term.climate.change..it.is.worth.mentioning.that.many.projects.adopted.integrated.water.resources.management.(iwrm).frameworks..iwrm.is.an.effective.way.to.position.water.issues,.address.water.quality.and.quantity.aspects.at.the.policy.and.local.level,.and.at.the.same.time.play.a.major.role.in.aiding.societal.adaptation.to.climate.change..iwrm.will.likely.decrease.the.vulnerability.of.freshwater.systems.to.climate.change.
Specific examples of management/operations interventions extracted from the portfolio are listed below without any particular preference on ranking:
•.implement.improved.water.management.practices,.including.bench.marking,.administration.of.water.entitlements,.and.bulk.supply.of.water.to.users.
•.Participatory.and.integrated.ecosystem.management.by.carrying.out.programs.to.implement.integrated.watershed.and.wetlands.management.strategies.
•.restore.operational.performance.and.safety.of.dams.•.develop.and.strengthen.key.wrm.instruments.such.as.the.formulation.of.a.detailed.participatory.
and.integrated.wrm.plans.for.basins,.bulk.water.distribution.models.and.decision.aid.tools.•.optimize.water.resource.utilization.and.enforce.water.use.rights.•.implement.conjunctive.management.of.groundwater.and.surface.water.•.invest.in.watershed.development.and.flood.management.for.climate.resilience.•.increase.water.flows.in.rivers.through.conservation.of.the.paramos.ecosystem.and.its.associated.
vegetation.•.implement.cyclone.risk.mitigation.investments.through.mangrove.plantations.and.coastal.zone.
management.works.•.develop.new.sustainable.financing.mechanisms.for.the.payment.of.environmental.services.
(watershed.conservation).through.water.tariff.
Infrastructure interventions are also represented in the active and pipeline projects with most interventions in LCR, SAR, EAP and AFR..water.infrastructure.is.defined.by.the.rehabilitation,.optimization.and.development.of.small.and.large.hydraulic.infrastructure.to.improve.the.management.of.water.resources.and.delivery.of.water.services.by.making.the.systems.more.resilient.to.the.changes.in.climate..some.examples.include—retrofitting.existing.infrastructure;.developing.multi-purpose.storage.and.attenuation.structures;.creating.long-term.structural.solutions.to.flooding;.rehabilitation.of.irrigation.schemes,.etc..it.is.important.to.note.that.infrastructure.rehabilitation.for.projects.categorized.as.recovery.or.emergency.operations.are.not.included.in.this.class.
Specific examples of infrastructure interventions extracted from the portfolio are listed below without any particular preference on ranking:
•.rehabilitate.and.modernize.water.infrastructure.(irrigation,.hydropower,.etc).•.create.long-term.structural.solutions.to.flooding,.including.the.construction.of.substantial.multi-
purpose.storage.and.attenuation.structures.
72
•.develop.hydropower.resources.in.an.environmentally.sustainable.and.socially.responsible.manner.•.build.long-term.preparedness.by.supporting.cyclone-resistant.infrastructure.rehabilitation,.
livelihood.restoration.and.vulnerability.reduction.•.support.the.construction.and/or.installation.of.storage/conveyance.structures.and.distribution.
networks.to.optimize.the.storage,.delivery,.and.use.of.water.supplies.•.build.water.harvesting.infrastructures,.including.valley.dams.and.reservoirs,.and.hillside.irrigation.
infrastructure.•.develop.groundwater.infrastructure.in.a.sustainable.manner.•.develop.small-scale.storage.structures,.crop.diversification.and.water.harvesting.for.farmers.
Capacity building and awareness are also important elements for the effective management and decision making of water resources, as well as for adaptation to climate change. with.most.interventions.in.AFr,.lcr,.eAP.and.sAr,.these.actions.will.build.local.capacity.and.raise.awareness.for.water.users.and.communities.about.how.they.can.play.an.expanded.role.in.the.management.and.decision.making.of.water.resources.and.adaptation.to.climate.change..this.is.achieved.by.building.local.capacity;.empowering.water.users.and.water.users’.associations;.engaging.communities.in.the.decision.framework,.offering.trainings,.and.implementing.awareness-raising.campaigns.at.the.community.and.user.level.to.promote.greater.responsibility.in.managing.water.resources.in.view.of.the.changing.climate.conditions.
Specific examples of this type of intervention taken from projects in the portfolio are given below without any particular preference on ranking:
•.technical.assistance.for.water.sector.capacity.building.to.carry.out.water.resources.investment.planning.
•.increase.climate.change.adaptation.awareness.of.water.user.associations,.technical.staff,.and.officials.
•.increase.civil.society.participation.in.the.decision.making.process.for.water.resource.management.
•.empower.water.users.and.strengthen.water.user.associations.in.order.to.enhance.their.capacities,.and.carry.out.necessary.operation,.maintenance.and.cost.recovery.functions.
•.Promote.participation.of.local.governments,.concerned.agencies.and.stakeholders.in.improving.flood.management.plans.
•.engage.communities.in.co-management.of.water.and.forest.resources.•.create.a.participatory.approach.to.sustainable.watershed.management.by.formation.of.
community.associations.to.manage.watershed.conservation.plans.
With a moderate representation in the portfolio, EAP, SAR and ECA are the regions that have invested the most in monitoring and information systems..Monitoring and information system interventions are vital actions to better forecast and monitor hydrological variability in water systems for the efficient, sustainable and equitable management of water resources and adaptation to climate change. Actions.include.the.development.and.improvement.of.water.resources.information.systems.with.monitoring,.modeling.and.prediction.capabilities,.weather.forecasting,.hydro-meteorological.data.collection,.early.flood.warning.and.response.systems,.etc..Any.action.involving.analysis.of.hydrological.trends.and.improvement.in.the.accuracy.of.forecasting.methods.is.key.for.effective.management.of.water.systems.and.for.the.design.of.new.ones..this.type.of.intervention.is.essential.for.long-term.planning,.and.especially.for.detecting.and.quantifying.the.impacts.of.climate.change.
73
Specific examples on Monitoring/Information System interventions extracted from the portfolio are listed below, without any particular preference on ranking:
•.upgrade.flood.and.storm.monitoring;.modeling.and.forecasting.capabilities;.and.enhance.early.warning.and.response.systems.
•.strengthen.capacity.in.data.analysis,.mapping.and.vulnerability.assessments.•.strengthen.water.quality.monitoring.laboratories.•.develop.hydro-meteorological.forecasting.systems.•.develop.vulnerability.and.ecological.mapping.(including.vulnerability.to.flood.and.erosion),.and.
create.demarcation.of.hazard.zones.susceptible.to.natural.disasters.and.flooding.•.establish.a.telemetry.system.for.real-time.measurement.of.water.availability.
Technology as an adaptation measure has much unexploited potential for scaling up..the.adaptation.interventions are.more.prominent.in.AFr,.eAP.and.lcr.with.a.wide.variety.of.measures.aiming.to.increase.water.use.efficiency,.or.incorporation.of.new.technologies.to.make.water.systems.more.resilient.to.climate.variability.and.change..some.examples.include.the.adoption.of.water.saving.technologies.such.as.treated.wastewater.reuse,.water.harvesting,.evapo-transpiration-based.water.resources.planning,.or.any.other.innovative.measure.to.increase.water.use.efficiency..some.technologies.are.applied.at.the.pilot.level.for.later.implementation.at.a.larger.scale.
Specific examples of technology interventions extracted from the portfolio are listed below without any particular preference on ranking:
•.develop.water-saving.technologies.(e.g..drip.irrigation).•.Promote.treated.wastewater.reuse.in.irrigation.on.a.sustainable.basis.•.improve.irrigation.systems.by.enhancing.water.use.efficiency.in.tank.areas.•.develop.improved.irrigation.technology.including.pressurization.of.surface.flows.to.replace.
groundwater.•.Adopt.evapotranspiration.measuring.technology.•.Adopt.soil.and.water.conservation.technologies.•.develop.water.harvesting.techniques.
Figure 6.10 Type of intervention for projects in FY06–08 and FY09–10
Management/Operations
19%
Technology/Innovation
11%
Capacity Bldg andAwareness
15%
Monitoring andInformation System
12%
FY06–08
Policy/Institution
27%
Infrastructure16%
FY09–10
Management/Operations
24%
Technology/Innovation
8%
Capacity Bldg andAwareness
15%
Monitoring andInformation System
9%
Policy/Institution
33%
Infrastructure11%
74
75
CHaPTer 7: exPosure of THe waTer PorTfolio To CurrenT HydrologiC variabiliTy and fuTure ClimaTe CHange
introduction
The World Bank’s investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide.some.sense.of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they.represent..results.of.the.projections.of.the.hydrologic.drivers.for.2030.and.2050,.discussed.earlier,.are.used.to.assess.the.exposure.of.the.portfolio..in.this.chapter,.investment.exposure.to.the.impact.of.climate.change.for.the.following.water.systems.is.assessed:.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation,.flood.control,.river.basin.management,.and.multi-purpose.(supply.water.for.multiple.purposes).
Risk is generally defined as the product of probability and consequence..given.that.the.probabilities.of.occurrence.of.different.climate.change.scenarios.are.not.known,.a.formal.risk.assessment.cannot.be.carried.out..rather,.an.evaluation.of.the.impacts.of.climate.change.on.bank.investments.is.carried.out.in.terms.of.changes.in.hydrologic.indicators.and.changes.in.the.level.of.exposure.of.the.investments.to.these.indicators..in.this.context,.exposure.is.loosely.equated.to.consequence.
For this assessment the A1B emissions scenario is chosen..this.scenario.is.suggested.by.many.to.be.the.closest.to.a.“business.as.usual.future”..Additionally.it.is.the.middle.range.of.emissions.and.resulting.global.mean.temperature.of.all.the.Ar4.sres.scenarios.as.discussed.earlier..given.that.the.interest.here.is.a.broad.overview.of.the.potential.exposure.of.world.bank.infrastructure.projects.particularly.those.with.the.life.extending.to.2050,.the.A1b.scenario.provides.the.central.tendency.of.scenarios.to.the.year.2050..Additionally.all.the.scenarios.are.tightly.bunched.until.2050.where.at.that.point.they.start.to.diverge.greatly.
Hydrologic indicator selected for assessment of each water system is given in Table 7.1..these.indicators.have.been.defined.earlier.in.connection.with.the.projections.analysis..An.indicator.has.been.chosen.to.represent.each.water.system.as.listed.below.
exposure criteria and investment exposure
Each water sector is given an exposure level based on an agreed exposure criteria..For.the.current.variability.analysis,.the.exposure.level.represents.the.water.sector’s.exposure.to.current.variability..For.the.future.exposure.analysis,.the.exposure.level.represents.the.water.sector’s.
Table 7.1 List of water systems and indicators
Water System Indicator
irrigation.and.drainage change.in.annual.net.irrigation.deficit
urban.water.supply.and.sanitation change.in.runoff.reliability
rural.water.supply.and.sanitation change.in.minimum.base.flow
Flood.control change.in.runoff.reliability
river.basin.management.and.multi-purpose.infrastructure change.in.basin.yield
76
exposure.to.climate.change.and.future.variability..the.exposure.criteria.is.categorized.as.low,.medium.or.high..A.low.exposure.level.means.that.there.is.little.to.no.concern.about.the.water.sector’s.exposure.to.current/future.climate.variability/change,.where.a.high.exposure.level.means.that.there.is.an.immediate.concern..A.medium.exposure.level.means.that.there.is.some.concern.and.further.analysis.is.necessary..the.ranges.for.the.low,.medium,.and.high.exposure.level.classifications.were.determined.for.each.indicator.
Exposure of the World Bank’s investment portfolio to future climate change is evaluated using the exposure level for each system and placing the investment (lending) value on that exposure..the.investment.exposure.is.calculated.by.multiplying.the.cost.of.each.project.allocated.to.the.water.system.times.the.number.of.gcm.results.that.fall.into.each.of.the.three.exposure.criteria—low.medium,.or.high..results.for.each.exposure.class.were.summed.to.yield.regional.values..the.total.investment.value.for.each.region.is.the.sum.of.the.cost.of.each.water.system.in.each.project.
Results of current and future exposure to variability and climate change are reported by World Bank regions and Bank-wide..the.exposure.is.represented.as.low,.medium,.or.high.as.previously.discussed..results.of.investment.portfolio.exposure.are.by.water.system,.world.bank.regions.and.the.world.bank.as.one.region..the.investment.portfolio.exposure.is.reported.as.monetary.amounts..Future.exposure.based.on.climate.change.is.reported.for.2030.and.2050..these.years.were.chosen.because.they.represent.times.in.the.future.that.are.important.for.current.infrastructure.planning.intersected.with.the.expected.realization.of.potential.climate.change.impacts..For.this.analysis,.reporting.changes.in.2030.relative.to.historical.is.the.decadal.average.from.2025.to.2035.relative.to.the.average.historical..this.is.also.true.for.reporting.2050;.represented.by.the.average.from.2045.to.2055.relative.to.the.average.historical.
exposure to current hydrologic variability and future climate change
For each project on the review list, an approximate latitude and longitude was estimated based on the information available in the project documents..For.projects.with.multiple.locations,.only.one.location.was.selected.based.on.the.size.of.the.city.or.population.and.its.proximity.to.the.water.source..each.project.was.then.mapped.to.a.0.5.degree.by.0.5.degree.grid.on.the.globe..the.percentage.change.of.the.related.hydrologic.indicator.for.the.projected.hydrologic.variables.for.2030.and.2050.was.also.mapped.on.the.same.grid.as.the.project.location.for.assessment.of.the.exposure..Assessment.of.exposure.for.each.water.system.for.each.region.is.described.and.the.results.reported.in.the.subsequent.sections.
A word on the limitation of this approach..it.should.be.noted.that.this.analysis.is.focused.on.the.future.changes.of.the.mean.of.the.hydrologic.drivers.only,.as.they.are.derived.from.the.mean.runoff.projections..in.many.cases.the.future.changes.of.variability.in.runoff.may.be.much.more.important.than.the.change.in.the.mean..many.projections.show.increases.in.variability.which.lead.to.more.extreme.events..For.example,.a.10%.change.in.runoff.variance.may.be.much.more.important.(potentially.many.times.more.damage).than.a.10%.change.in.the.mean.runoff..evaluating.the.impacts.of.variability.on.investments.is.outside.the.scope.of.this.analysis,.but.should.be.highly.considered.for.future.work.
Irrigation and drainage
Irrigation and drainage is represented by the change in annual net irrigation deficit..this.is.determined.using.the.water.deficit.index.(wdi).which.is.the.difference.between.the.precipitation.and.crop.water.requirement..table.7.2.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.1.
77
shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.2.shows.exposure.map.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region.
Urban water supply and sanitation
Urban water supply and sanitation is represented by the change in runoff reliability..runoff.reliability.is.determined.using.a.flow.duration.(frequency).curve.(Fdc)..A.Fdc.is.generated.by.plotting.the.percentage.of.time.that.a.flow.rate.is.greater.than.or.equal.to.a.given.flow.rate..this.indicator.is.taken.as.the.flow.that.is.exceeded.90%.of.the.time.(q90).which.means.there.is.a.10%.chance.in.each.time.period.of.a.flow.lower.than.this..if.this.q90.decreases.it.means.that.the.likelihood.of.low.flows.and.droughts.will.likely.increase..table.7.3.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.3.shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.4.shows.the.exposure.map.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region.
Rural water supply and sanitation
Rural water supply and sanitation is represented by change in minimum base flow as a proxy for groundwater availability..it.is.assumed.that.the.groundwater.contribution.to.runoff.can.be.model.as.a.“linear.reservoir”.where.base.flow.is.combination.of.a.groundwater-surface.water.interaction.coefficient.multiplied.by.the.groundwater.storage.in.the.month..table.7.4.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.5.shows.the.exposure.map.for.2030.
Table 7.2 Irrigation and drainage exposure level descriptions
Exposure Level Description
low %.change.in.annual.water.deficit.index.<.5%
medium %.change.in.annual.water.deficit.index.between.5%.and.15%
High %.change.in.annual.water.deficit.index.>15%
Table 7.3 Urban water supply and sanitation exposure level description
Exposure Level Description
low %.change.in.runoff.reliability(–90%).>–5%
medium %.change.in.runoff.reliability(–90%).between.–5%.and.–15%
High %.change.in.runoff.reliability(–90%).<–15%
Table 7.4 Rural water supply and sanitation exposure level description
Exposure Level Description
low %.change.in.minimum.base.flow.>–5%
medium %.change.in.minimum.base.flow.between.–5%.and.–15%
High %.change.in.minimum.base.flow.<–15%
78
for.the.middle.projection.for.all.bank.regions..Figure.7.6.shows.the.exposure.maps.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region.
Flood Control
Flood control is represented by the change in runoff reliability..runoff.reliability.is.determined.using.a.flow.duration.(frequency).curve.(Fdc)..A.Fdc.is.generated.by.plotting.the.percentage.of.time.that.a.flow.rate.is.greater.than.or.equal.to.a.given.flow.rate..this.indicator.is.taken.as.the.flow.that.is.exceeded.10%.of.the.time.(q10).which.means.there.is.a.90%.chance.in.each.time.period.of.a.flow.lower.than.this..if.this.q10.increases.it.means.that.the.likelihood.of.higher.flows.and.floods.will.likely.increase.
table.7.5.shows.the.criteria.used.to.assess.the.levels.of.exposure..Figure.7.7.shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.8.shows.the.exposure.maps.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region.
River basin management and multi-purpose infrastructure
River basin management is represented by the change in basin yield..the.basin.yield.is.a.measure.of.annually.reliable.water.supply.from.the.basin..basin.yield.is.directly.related.to.the.amount.of.reservoir.storage.in.a.basin..A.storage-yield.curve.is.used.to.mathematically.represent.the.basin.yield..table.7.6.shows.the.criteria.used.to.assess.the.levels.of.exposure.
Figure.7.9.shows.the.exposure.map.for.2030.for.the.middle.projection.for.all.bank.regions..Figure.7.10.shows.the.exposure.maps.for.2030.and.2050.for.the.driest,.middle,.and.wettest.projections.for.the.Africa.region.
Table 7.5 Flood control exposure level description
Exposure Level Description
low %.change.in.runoff.reliability(-10%).<5%
medium %.change.in.runoff.reliability(-10%).between.5%.and.15%
High %.change.in.runoff.reliability(-10%).>15%
Table 7.6 River basin management exposure level description
Exposure Level Description
low %.change.in.basin.yield.<5%
medium %.change.in.basin.yield.between.5%.and.15%
High %.change.in.basin.yield.>15%
Note: Historic.yield.=.75%.of.Historical.Annual.runoff
79
Figure 7.2 Projected 2030 and 2050 exposure maps to change in water deficit index – Africa Region
Figure 7.1 Projected 2030 exposure map to change in water deficit index
Low Medium High
Low Medium HighIrrigation Deficit
80
Figure 7.4 Projected 2030 and 2050 exposure maps to change in low flows (drought) – Africa Region
Figure 7.3 Projected 2030 exposure map to change in low flows (drought)
Low Medium High
Low Medium HighLow Flow
81
Figure 7.6 Projected 2030 and 2050 exposure maps to change in base flow – Africa Region
Figure 7.5 Projected 2030 exposure map to change in base flow
Low Medium HighBase Flow
Low Medium High
82
Figure 7.8 Projected 2030 and 2050 exposure maps to change in high flows (floods) – Africa Region
Figure 7.7 Projected 2030 exposure map to change in high flows (floods)
Low Medium High
Low Medium HighHigh Flow
83
Figure 7.10 Projected 2030 and 2050 exposure maps to change in basin yield – Africa Region
Figure 7.9 Projected 2030 exposure map to change in basin yield
Low Medium High
Low Medium HighBasin Yield
84
Potential exposure of the investment portfolio
The World Bank’s investments in the water sector are highly exposed, both to current variability and future climate change..the.purpose.of.this.assessment.is.to.provide.some.sense.of.magnitude.of.the.exposure.of.the.projects.and.the.financial.investments.they.represent..using.threshold.criteria.for.changes.in.each.indicator,.maps.were.created.for.high,.medium,.and.low.exposure.categories.for.each.indicator..water.projects,.classified.by.water.systems,.are.superimposed.on.the.appropriate.exposure.map..the.outcome.is.an.exposure.categorization.of.each.water.system.according.to.its.respective.indicator..in.this.analysis,.exposure.to.the.impact.of.climate.change.for.the.following.water.systems.on.the.bank.portfolio.is.assessed:.irrigation.and.drainage,.urban.water.supply.and.sanitation,.rural.water.supply.and.sanitation,.flood.control,.river.basin.management,.and.multi-purpose.(supply.water.for.multiple.purposes)..results.of.the.potential.exposure.of.the.active.bank.water.investments.were.they.to.operate.in.2030.and.2050.are.available.
Bar charts on Figures 7.11 and 7.12 show the level of exposure of the Bank water investments to climate change by volume of investment and number of projects by region and Bank-wide..similar.charts,.categorized.by.water.systems,.are.available.for.each.region.and.bank-wide.
Projections indicate that about half of the Bank water projects reviewed would potentially be at high to medium level of exposure to climate change impacts in 2030 (Figure 7.11)..within.each.regional.portfolio,.eAP.shows.close.to.two-third.of.projects.with.potential.exposure.to.high/medium.risk,.possibly.due.to.increased.flooding..AFr.and.lcr.show.about.half.of.the.projects.and.mnA.some.40%.at.potential.high.to.medium.risk.of.exposure..ecA.and.sAr.show.about.one-third.of.the.projects.at.potential.risk.of.exposure.to.hydrologic.changes..Projections.for.2050.show.exposure.increasing.for.all.regions.except.eAP..obviously,.the.level.of.uncertainty.related.to.projecting.climate.change.so.far.in.time.would.be.too.high.to.make.much.of.this.difference.
Figure 7.11 Exposure of water projects to climate change in 2030 and 2050
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Ban
kwid
e
2030
% o
f wa
ter p
roje
cts
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Ban
kwid
e
2050
% o
f wa
ter p
roje
cts
Low Med High
85
In terms of investments, about half of the total water investments (including the pipeline) are projected at high/medium exposure level to climate change impacts in the 2030 decade (Figure 7.12)..this.translates.to.approximately.$.10.billion.on.the.Fy06–10.water.projects.reviewed.here,.risk.associated.with.approval,.delay,.or.drop.of.pipeline.projects.notwithstanding..the.pattern.of.risk.of.exposure.of.investment.roughly.follows.that.of.the.projects..For.2050,.climate.change.projections.show.an.increase.in.mnA,.AFr,.lcr,.and.ecA,.while.expected.to.decrease.in.eAP,.and.sAr..Again,.the.uncertainty.associated.with.the.climate.change.projections.in.2050.is.considered.quite.high.and.therefore.this.conclusion.should.be.viewed.with.caution.
Figure 7.12 Exposure of water investments to climate change in 2030 and 2050
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Ban
kwid
e
2030
% o
f wa
ter p
roje
cts
0
20
40
60
80
100
EAP
ECA
LCR
MN
A
SAR
AFR
Ban
kwid
e
2050
% o
f wa
ter p
roje
cts
Low Med High
86
87
CHaPTer 8: risk-based deCision making for ‘ClimaTe smarT’ invesTmenTs
introduction
There is evidence of an intensification and acceleration of the hydrologic cycle due to climate change, but this is subject to a high degree of uncertainty. Analysis.in.the.previous.chapter.illustrates.the.exposure.of.the.bank’s.water.investments.to.the.potential.impact.of.hydrologic.variability.and.climate.change..while.the.best.available.science.was.used,.there.is.still.substantial.uncertainty.regarding.the.real.effects.of.climate.change,.generally,.and.by.extension.on.the.hydrologic.cycle.and.ecosystem.responses..there.have.been.major.advances.in.projecting.impacts—both.from.general.circulation.models.and.downscaling/statistical.methods—which.allows.reporting.general.trends.with.some.degree.of.confidence.(including.in.temperature,.precipitation,.and.extreme.events)..However,.there.are.still.significant.unknowns,.and.even.more.challenging.“unknown.unknowns”..there.is.no.way.around.these.uncertainties.given.the.current.state.of.the.science—even.agreement.on.a.particular.phenomenon.across.multiple.models.does.not.‘prove’.that.a.given.projection.will.indeed.come.to.pass.
Reducing the water sector’s vulnerability to climate change means managing water under conditions of uncertainty. there.are.three.options.for.dealing.with.uncertainties.(i).wait.until.science.is.“better”.at.making.projections;.(ii).insist.on.pushing.modeling.efforts.to.their.limits,.and.beyond;.and.(iii).take.uncertainty.as.a.given.and.try.manage.it..the.first,.wait.and.see,.approach.could.be.dangerous.and.costly.in.the.longer.run.24.the.second.could.also.be.hugely.risky,.that.is,.such.an.approach.could.lead.to.projections.and.actions.based.on.them.that.are.‘precisely.wrong.’.it.is.the.third.that.holds.the.most.promise..this.approach.is.relevant.to.all.sectors,.but.it.is.particularly.so.in.the.case.of.the.water.sector.because.of.the.direct.link.between.climatic.conditions.and.hydrology.and.environmental.sustainability.
Water professionals have traditionally dealt with climate variability, but climate-change introduces uncertainties in both the future mean values and variability. water.professionals.have.routinely.dealt.with.natural.climate.variability.(inter.and.intra-annual).and.climate-related.hazards.such.as.droughts.and.floods.in.delivering.water.services.and.managing.water.resources..but,.they.have.historically.done.so.under.the.key.assumption.of.a.stationary.hydrologic.pattern:.the.mean,.variance.and.standard.deviation.of.hydrologic.time.series.is.fixed.over.time..this.assumption.enabled.decision-makers.to.estimate.hydrologic.risks.to.water.systems,.or,.in.other.words,.to.establish.with.some.degree.of.certainty.both.potential.outcomes/impacts.and.the.probability.of.their.occurrence..climate.change.introduces.new.uncertainties,.both.in.respect.to.the.future.mean.values.and.variability,.but.also.in.respect.of.uncertainty.and.the.chance.of.outcomes.that.may.be.very.different.from.any.historic.experience.
Climate change calls into question the classical assumption that past hydrologic knowledge provides a good guide to future conditions in planning, designing and operating water investments..it.is.now.well-accepted.that.the.future.hydrologic.regime.will.not.be.a.statistical.replica.of.the.past,.but.there.are.significant.unknowns.as.to.precisely.how.hydrologic.characteristics.will.change..thus,.the.challenge.confronting.water.professionals.is.
24 Indeed,ThomasSchelling,winnerofthe2005NobelPrizeinEconomics,notesthattheideathatactionsareunwarrantedifthedangersareuncertainisalmostuniquetoclimatechange.Inotherareasofpolicy,suchasterrorism,nuclearproliferation,inflation,orvaccination,some‘insurance’principleseemstoprevail:ifthereissufficientlikelihoodofsignificantdamage,typicallysomemeasuredanticipatoryactionistaken.(Economists’Voice,www.bepress.com/ev,July2007).
88
how.to.plan,.design.and.manage.when.the.confidence.in.calculations.of.risk.are.substantially.lowered.because.either.the.potential.outcomes.or.the.probability.of.their.occurrence—or.both—are.largely.unknown..there.are—and.have.always.been—many.sources.of.uncertainty.other.than.hydrology.that.are.important.to.water.management,.including.changes.in.population,.income.levels,.technology,.ecosystem.functions.and.services.and.societal.values..However,.it.is.the.increase.in.hydrologic uncertainty.and.the.reduced.ability.to.calculate.hydrologic risks.that.make.water.management.with.and.without.climate.change.fundamentally.different.
Water investment planning, design and operations require a formal risk-based analysis in all aspects of the project/program cycle..water.systems.are.subject.to.both.climate.and.non-climate.related.stresses,.but.there.are.certain.types.of.water.investments.where.uncertainties.related.to.climate.change.could.have.a.significant.impact,.and.so.particular.care.needs.to.be.taken.in.undertaking.a.detailed,.rigorous.risk.assessment..these.include.highly.capitalized.or.unique.projects,.irreversible.investments,.engineering.structures.with.long.lifetimes,.long-lived.benefits.and.costs,.etc..examples.include:.single.and.multi-purpose.hydraulic.infrastructure,.interbasin.water.transfer.schemes,.water.conveyance.systems.for.irrigated.agriculture,.and.regional/transboundary.investments..yet,.there.are.water.systems.that.are.inherently.resilient.to.some.degree.of.hydrologic.variability.and.climate.change,.are.not.significantly.impacted,.or.the.consequents.of.impact.can.be.readily.remedied..in.these.cases,.a.less.rigorous.risk.assessment.(screening.level).may.be.sufficient.
Bayesian decision analysis framework one that allows for explicit characterization of risks, options, and management of risks..the.approach.incorporates.unfolding.uncertainties.over.time.and.accounts.for.the.performance.of.those.options.(Hobbs,.et.al,.1997)..in.bayesian.decision.analysis,.the.‘decision.problem’.is.structured.as.a.decision.tree,.in.this.specific.case.for.evaluating.options.under.various.climate.scenarios..uncertainty.is.incorporated.through.the.use.of.subjective.probabilities.for.the.scenarios.in.evaluating.the.expected.outcome.of.the.options.
this.chapter.addresses.the.necessity.for.incorporation.of.a.formal.risk-based.approach.in.water.investments,.the.overarching.themes/issues.to.be.considered.at.various.phases.of.project/program.cycle,.a.framework.for.risk-based.decision.making.adapted.from.the.current.state-of-the-knowledge,.and.how.such.a.framework.may.be.applied.to.the.bank’s.project.cycle.
sector investment decisions must be made under increased risk and uncertainty
Risk management is a good practice for water management that makes sense even if the climate were not a consideration..the.application.of.risk.management.is.more.applicable.when.climate.change.is.considered..Although.we.know.the.climate.is.changing.and.will.continue.to.change,.it.is.not.possible.to.make.a.precise.prediction.as.to.exactly.how.and.when.climate.will.change..At.best,.a.range.of.potential.changes.in.climate.can.be.identified..this.wide.range.of.potential.changes.in.climate.provides.justification.for.applying.principles.of.risk.management.to.manage.water.resources..it.is.more.imperative.to.consider.the.risks.that.climate.change.can.bring.and.manage.systems.appropriately.to.reduce.or.minimize.risks,.particularly.those.of.greatest.concern.
Water managers now face unprecedented challenges to investments in and management of water resources and services..in.the.past,.water.managers.often.recognized.that.the.systems.they.built.and.managed.were.vulnerable.to.hydrologic.variability,.population.growth,.and.other.
89
pressures.and.challenges..the.typical.response.to.such.vulnerabilities,.however,.was.to.factor.in.large.margins.of.safety.that.reduced.the.risk.of.an.adverse.event.(e.g.,.for.potential.water.supply.shortages—transfer.water.between.river.basins;.for.potential.urban.flooding—install.high.capacity.storm.water.infrastructure)..Furthermore,.they.assumed.the.climate.was.stationary—the.likelihood.and.magnitude.of.extreme.climate.events.as.well.as.average.climate.conditions.were.known.based.on.historical.records..thus,.it.was.thought.that.systems.could.be.designed.and.operated.to.better.manage.adverse.events.(e.g.,.inadequate.water.supplies,.floods).by.reducing.the.frequency.and/or.magnitude.of.failure..Past.investment.decisions.have.incorporated.uncertain.future.trends,.such.as.population.movement.from.rural.to.urban.areas.shifting.the.geographical.distribution.of.water.demand,.population.growth.increasing.total.water.demand,.new.irrigation.technologies.increasing.effective.supply,.new.thermoelectric.power.plants.causing.spikes.in.water.demand,.the.possibility.of.drought.affecting.water.supply.in.any.given.year,.and.more..many.past.water.systems.have.successfully.provided.safe.and.reliable.water.supplies.and.other.services.despite.these.uncertainties—climate.change.simply.adds.one.more.uncertainty.to.the.list.water.managers.have.successfully.tackled.for.generations.
The margin of safety built into water projects often entails investing significant resources to avoid low probability, high consequence risks..the.opportunity.cost.of.factoring.in.such.large.safety.margins.was.once.non-controversial,.but.resource.scarcity,.escalating.costs,.and.expansion.in.demand.for.water.resources.and.services.as.well.as.increasing.environmental.and.degradation.and.awareness.have.put.significant.pressure.on.water.managers.to.reduce,.manage.or.contain.costs.while.expanding.services..consequently,.the.acceptable.margin.of.safety.for.water.resources.and.services.has.narrowed..compounding.these.difficult.realities,.climate.change.adds.a.new.challenge.that.further.complicates.the.operational.environment.by.replacing.the.conventional,.stable,.but.variable,.hydrological.baseline.with.a.new.one.to.include.changing.average.conditions.as.well.as.changing.variability..However,.this.new.baseline.cannot.be.estimated.with.a.great.degree.of.certainty.
Current understanding of climate and climate change indicates that historical data is no longer the only reliable guide to future climate events.25.whereas.scientists,.engineers,.and.water.managers.previously.considered.the.climate.to.be.stationary,.we.now.understand.that.climate.is.subject.to.a.number.of.forces.that.cause.averaged.conditions.and.extremes.to.change.over.time..For.example,.engineers.typically.design.flood.control.structures.based.on.an.engineering.standard.(e.g.,.design.to.withstand.a.100-year.flood).and.historic.stream.flow.and.flooding.data.inform.that.standard.(e.g.,.a.1%.chance.of.flood.waters.exceeding.10.meters.in.any.given.year.based.upon.150.years.of.historical.data)..in.other.words,.designing.for.a.100.year.flood.under.the.recent.past.might.equate.to.designing.for.a.50.or.even.a.20.year.event.in.future.decades.(or,.alternatively,.to.design.for.the.100.year.flood.of.the.future,.we.may.need.to.design.for.what.we.currently.consider.to.be.a.500.year.flood).
Future decision making will be further complicated because climate is changing and the rate of that change is likely to accelerate..even.accounting.for.recent.climate.trends.e.g.,.the.observed.rate.of.sea.level.rise,.may.not.be.sufficient.to.prepare.for.climate.change..but,.it.is.not.possible.to.precisely.forecast.future.climate.conditions:.we.cannot.precisely.predict.future.emissions.of.greenhouse.gases,.nor.can.we.accurately.project.the.change.in.climate.variables.that.will.result.from.those.changes.in.greenhouse.gases,.or.the.change.in.hydrology.that.will.result.
25 Tobesure,climatehasneverbeenstationary.Climateshavealwayschangedfornaturalreasonssuchaschangesinsolarradiation,theearth’sorbitaroundthesun,andotherfactors.Whatisnewistheadditionofhumancausedclimatechange.
90
from.those.changes.in.climate..this.is.particularly.true.at.the.geographic.scale.relevant.to.most.water.resources.and.services,.which.are.typically.managed.at.the.river.basin.level,.the.individual.water.supply.source,.or.the.specific.treatment.facility.or.other.water.system..consequently,.water.managers.must.always.make.investment.and.operational.decisions.under.uncertainty.
The good news: making decisions under uncertainty is neither new nor unique to water investments..making.decisions.under.uncertainty.requires.an.adequate.accounting.of.the.risks.faced.under.different.options.and/or.different.projected.future.conditions..Armed.with.an.understanding.of.the.options.available.to.them,.water.managers.must.weigh.the.tradeoffs.associated.with.making.alternative.choices.about.which.risks.to.reduce.and.which.ones.to.bear..in.some.cases,.a.risk.will.be.so.unacceptable.that.the.old.paradigm.of.simply.building.in.expensive.safety.factors.may.be.the.best.choice.(e.g.,.overbuilding.dams.to.ensure.they.will.not.fail)..in.other.cases,.strategies.exist.to.reduce.the.consequences.of.an.adverse.event.while.reducing.the.costs.of.a.water.investment.(e.g.,.instead.of.retrofitting.inadequate.storm.water.drainage.infrastructure,.build.above.ground.culverts.and.protect.low.lying.land.downstream.from.development.to.provide.a.natural.floodplain)..such.strategies,.discussed.below,.allow.for.less.expensive.and.oftentimes.more.effective.water.systems.and.services.
Given the policy, financial implications of making water investment decisions, a more systematic approach is needed for water investment decision making..we.call.the.systematic.approach.proposed.in.this.chapter.risk-based decision making..risk-based.decision.making.considers.uncertainty.explicitly.(not.only.applicable.where.‘risk’.can.be.quantified).in.the.evaluation.of.probabilities.and.consequences.associated.with.alternative.investment.strategies.as.well.as.strategies.to.make.informed.decisions.in.the.face.of.irreducible.uncertainty.
Water managers have two choices—to ignore the changing risks posed by altered climate and hydrology and rely only on historic data or to use risk-based decision making..in.spite.of.the.problematic.uncertainty.associated.with.changing.climate.baselines,.precedents.of.risk-based.decision.making.by.water.managers.exist..this.chapter.first.discusses.risk-based.decision.making..it.includes.a.discussion.of.tools.for.implementing.a.risk.management.approach.and.measuring.vulnerability..then,.the.chapter.builds.on.the.analysis.of.risk.management.to.examine.adaptation.to.climate.change..the.focus.will.be.on.the.types.of.adaptations.that.make.sense.given.what.is.known.about.climate.change.
a framework for risk-based decision making for water investments
Definitions and terminology
According to the U.S. National Research Council, risk analysis has two components—risk assessment and risk management..risk.assessment.is.the.factual.basis.for.defining.adverse.events.and.determining.their.probabilities.and.consequences..risk.management.is.the.process.of.weighing.policy.alternatives.in.response.to.risk..risk.assessment.is.further.decomposed.into.risk.identification—determining.whether.a.particular.event.has.adverse.consequences,.and.risk.characterization—describing.the.nature.and.magnitude.of.the.risk.(nrc.1983,.1994)..However,.various.institutions,.fields.of.study,.and.sectors.use.these.terms.differently.or.use.their.own.language.to.describe.these.or.similar.concepts..For.example,.the.u.s..Army.corps.of.engineers.identifies.four.steps.to.risk.analysis:.risk.characterization,.risk.quantification,.risk.evaluation,.and.risk.management.(usAce.1992)..while.some.overlap.with.the.nrc.terminology.is.evident,.there.are.some.differences.
91
Because these differences in terminology permeate all discussions of risk, establishing some basic terminology is necessary..in.the.most.basic.sense,.risk.itself.has.two.components:.a.consequence.component.(the.magnitude.of.harm.should.the.event.occur).and.a.probability.component.(the.likelihood.that.an.adverse.event.will.occur)..risks.can.quickly.be.classified.along.these.lines.as.shown.in.Figure.8.1..this.view.of.risk.has.become.quite.commonplace.
The consequence component of risk refers to the magnitude of harm should an adverse event occur..consequence.is.a.function.of.both.the.adverse.event.itself.and.the.affected.system..A.tropical.cyclone.striking.an.uninhabited.area.may.have.little.consequence.for.society..the.same.storm.striking.a.populated.area.may.have.greater.consequences.
The probability component refers to the likelihood of an adverse event occurring..by.convention,.the.word.risk.sometimes.refers.only.to.this.probability.component,.also.known.as.event.risk..we.define.risk.more.broadly.to.include.the.consequence.component..establishing.the.probability.of.an.undesirable.event.can.be.challenging,.especially.when.conditions.are.changing.(e.g.,.socioeconomic.conditions)..establishing.reliable.probability.estimates.under.climate.change.is.even.harder,.and.in.many.cases,.impossible.
Figure 8.1 displays probability and consequence of events with similar and different effects..events.A.and.c.have.similar.consequence..but,.event.c.has.higher.probability.than.event.A..so,.event.c.would.be.of.greater.concern.to.a.risk.manager..event.d.is.as.likely.to.happen.as.frequently.as.event.c,.but.has.less.consequence..so,.event.d.would.be.of.lesser.concern..event.b.has.moderate.probability,.but.relatively.low.consequence..it.would.be.of.less.concern.than.events.d.and.
Box 8.1 Risk and Uncertainty
risk.and.uncertainty.are.typically.differentiated.on.the.basis.of.probability.uncertainty,.specifically.whether.or.not.
objectively.known.probability.distributions.can.be.used.to.describe.potential.outcomes..in.risk.situations,.they.
can;.in.uncertain.situations,.they.cannot..the.boundaries.between.risk.and.uncertainty.are,.however,.not.clear-
cut..risk.and.uncertainty.can.be.envisioned.as.intermediary.points.on.a.continuum.of.knowledge.from.complete.
certainty.to.complete.ignorance,.as.shown.in.the.below.diagram..the.right.end.of.the.continuum.is.comprised.
of.objective.risks..Proceeding.to.the.left,.probabilities.become.less.statistically.sound.and.gradually.merge.into.
subjective.probabilities..Finally,.at.the.end.of.the.continuum,.no.probabilities.can.be.assigned.
Complete Ignorance Uncertainty Risk Complete Certainty
No Probabilities Subjective Probabilities Objective Probabilities
Figure 8.1 Consequence and probability components of risk
A C
DBC
onsequence
Probability
Extreme High Moderate Low
92
c,.which.have.higher.probabilities.of.occurring.and.have.greater.consequence..whether.event.b.would.be.of.greater.concern.than.event.A.depends.on.the.relative.consequences.and.probabilities.of.these.two.events..in.this.diagram,.event.b.is.considered.to.be.of.moderate.concern,.less.than.event.A,.but.this.is.a.value.judgment..it.may.be.possible.that.a.relatively.low.probability.event.such.as.A.may.be.of.higher.concern.than.event.d.because.the.consequences.of.A.are.quite.high.or.unacceptable.(e.g.,.the.probability.of.an.upstream.ice.dam.breaking.free.and.flooding.downstream.may.be.extremely.low,.but.the.consequences.may.be.unacceptably.high,.e.g.,.if.flooding.will.result.in.loss.of.many.lives.and.destruction.of.much.property).
Distinctions exist between exposure, sensitivity, and adaptive capacity (e.g., Smit et al., 2001)..exposure.is.the.frequency.of.a.climate.event.occurring.and.the.magnitude.of.the.event.itself.(e.g.,.the.likelihood.of.a.category.3.tropical.cyclone.striking.a.coastal.area)..exposure.is.also.a.function.of.the.location.and.size.of.a.system.that.can.be.affected.by.the.event..nairobi.is.not.exposed.to.sea.level.rise,.but.mombasa.is..sensitivity.is.the.extent.to.which.an.exposed.system.will.be.affected.(e.g.,.a.low.lying.heavily.populated.coastal.area.may.be.very.sensitive.to.a.category.3.tropical.cyclone)..the.dutch.are.less.sensitive.to.sea.level.rise.because.they.have.built.defenses,.while.bangladesh.lacks.sufficient.defenses.and.is.more.exposed..Finally,.adaptive.capacity.is.the.ability.of.the.system.to.cope.or.adapt.to.the.event.or.change.in.conditions.such.as.change.in.climate..developed.countries.generally.have.more.adaptive.capacity.than.developing.countries..the.exposure,.sensitivity,.and.adaptive.capacity.of.the.affected.system.are.collectively.known.as.vulnerability.
In water management, the probability of occurrence of an event of significant consequence (e.g., a flood) often cannot be controlled..However,.exposure.(e.g.,.location.of.critical.assets),.sensitivity.(e.g.,.hard.versus.soft.infrastructure),.and.adaptive.capacity.(e.g.,.evacuation.capability,.level.of.development).are.factors.that.to.some.degree.can.be.controlled..because.there.is.often.little.a.water.manager.can.do.to.decrease.the.probability.of.an.adverse.climate.event,.water.managers.must.look.to.policy.interventions.that.reduce.exposure.of.affected.systems.and.sensitivity.in.order.to.address.most.climate-related.risks.to.water.investments.
Top-down approach to decision making focuses on the probability of an adverse event resulting from climate change..An.attempt.is.first.made.to.characterize.the.likelihood.that.there.will.be.an.adverse.event..this.characterization.is.often.difficult.to.establish.under.the.best.of.circumstances.due.to.nonlinearities.in.the.climate.and.biophysical.system,.multiple.interacting.variables,.temporal.effects,.ignorance.of.confounding.variables,.and.so.forth..nevertheless,.an.assessment.of.probability.is.generally.worthwhile.as.part.of.a.holistic.approach.to.risk-based.decision.making..in.regards.to.climate.change,.top-down.assessments.use.the.output.of.computer.models.to.project.changes.in.climate.and.the.consequent.impacts.on,.for.example,.water.systems..results.are.used.to.understand.the.vulnerability.of.a.system,.and.adaptations.can.then.be.designed.to.reduce.those.vulnerabilities.
Bottom-up decision making involves investigating the exposure, sensitivity, and adaptive capacity of the system of concern..water.managers.often.use.a.bottom.up.approach.in.their.operational.decision.making.to.determine.the.consequences.of.an.adverse.event.without.getting.bogged.down.in.modelling.of.probabilities.resulting.from.multiple.climate.models.as.models.of.biophysical.systems..Assessments.of.potential.damages.from.a.flood.event,.the.flow.capacity.of.storm.water.systems,.or.the.ability.of.different.water.users.to.sustain.a.period.of.water.unavailability.are.all.examples.of.focusing.on.the.consequences.and.system.vulnerability..Again,.this.is.an.important.element.of.risk-based.decision.making.and.should.generally.be.done.in.conjunction.with.identifying.system.objectives..in.regards.to.climate.change,.bottom-up.assessments.look.at.the.affected.system.instead.of.climate.models..such.assessments.determine.thresholds.at.which.
93
changes.in.climate.may.pose.significant.consequences.in.terms.of.operational,.safety,.or.other.concerns..the.bottom-up.approach.starts.with.knowledge.of.the.project.or.system,.rather.than.of.climate..this.can.be.easier.for.water.managers.to.apply.because.they.can.rely.on.their.knowledge.of.their.water.resource.systems,.rather.than.trying.to.master.output.of.climate.change.models.
Because climate change risk-based decision making is inherently concerned with the future, it must incorporate information about projected changes that may not be reflected in historical records..this.entails.significant.uncertainty.both.about.the.probability.and.the.consequence.of.an.adverse.event..while.the.best.possible.information.should.be.gathered.about.the.probabilities.of.adverse.events,.recognizing.the.limitations.of.such.knowledge.allows.water.managers.to.consider.different.types.of.policy.responses.to.manage.the.risks,.such.as.those.discussed.below..both.top-down.and.bottom-up.approaches.can.be.used.to.identify.the.change.in.climate.that.can.increase.vulnerability.beyond.some.critical.threshold..while.top-down.assessments.are.often.limited.to.the.outputs.of.models,.development.of.adaptations.typically.requires.extensive.knowledge.of.a.system,.that.is,.a.bottom-up.approach.
Risk-based decision framework
Risk-based decision making is the systematic consideration of the probabilities, consequences, and values associated with different decision alternatives..risk-based.decision.making.is.the.process.of.choosing.among.alternative.courses.of.action.to.achieve.a.defined.objective.based.upon.an.assessment.of.the.probability.of.an.adverse.event,.the.vulnerabilities.of.the.system.(e.g.,.the.water.investment).to.that.adverse.event,.and.values.associated.with.outcomes.(e.g.,.which.risk.should.most.be.avoided)..there.are.many.risk.assessment.frameworks.in.many.sectors.(willows.and.connell,.2003,.broadleaf.and.mjA,.2006)..A.brief.review.of.two.frameworks.for.risk-based.assessment.of.climate.change.is.provided.in.Annex.b..the.discussion.below.is.adapted.from.these.two.sources.and.for.application.to.the.water.sector..in.general,.risk-based.approach.involves.the.following.general.stages:.project.objectives.definition.and.characterization.of.the.system.components;.knowledge.of.the.likelihood.and.consequences.of.adverse.events.that.could.compromise.those.objectives;.identification.of.the.options.for.adapting.the.system.or.project.to.render.it.less.vulnerable.in.the.face.of.the.identified.risks;.and.assessment.(either.quantitatively.or.qualitatively).of.adaptation.options..A.schematic.of.the.decision.framework.is.given.in.Figure.8.2..these.stages.are.described.below.in.more.details.
Stage 1 – Identify problem, objectives, performance criteria and rules for decision-making
this.initial.stage.includes.the.following.steps:
1..define.decision.problem.and.objectives—identify.exposure.units/receptors.(i.e.,.system.of.interest).and.timeframe,.establish.overall.objectives.
Figure 8.2 Stages in risk-based decision making
Objectives CharacterizationAnalysis
Risk Assessment Adaptation OptionsIdentification & Assessment
94
2..establish.‘success’.or.‘performance’.criteria.and.associated.thresholds.of.tolerable.risk..success.criteria.are.measures.(indicators.and.values).against.which.adaptation.options.will.eventually.be.appraised.(e.g.,.effectiveness,.flexibility,.implementability,.economic.efficiency,.etc.)..criteria.may.express.the.risk.preference.of.decision-makers.(e.g.,.system.reliability.reached.90%.of.the.time)..criteria.that.are.of.particular.relevance.to.water.systems.are.reliability,.robustness.and.resilience.(discussed.in.depth.later.in.this.chapter)..these.are.sometimes.referred.to.as.the.‘threshold-type’.metrics.(stakhiv,.2009).as.opposed.to.‘absolute’.metrics.such.as.reservoir.elevation,.in-stream.flow.minima,.electricity.generation,.or.monetary.flood.damages).
3..identify.rules.for.decision-making.that.will.be.applied.to.evaluate.options.(below),.also.reflecting.risk.preference.of.decision-makers..rules.could.include.cost.benefit.analysis;.cost.effectiveness.analysis;.multi-criteria.analysis..risk.preference.could.include.risk.aversion,.etc..Figure.8.3.shows.the.template.for.stage.1.
Stage 2 – Assess risks
this.stage.includes.the.following.steps:
1..identify.the.climate.and.non-climate.variables.that.could.influence.potential.outcomes,.i.e.,.that.the.exposure.unit.is.potentially.sensitive/vulnerable.to.(e.g..create.pathways.linking.important.variables.to.exposure/units.and.decision.criteria).
2..identify.the.alternative.future.states.or.circumstances.that.may.occur.(both.climate.and.non-climate),.and.the.impact.of.these.on.the.exposure.unit.and.performance.criteria.(including.the.relative.importance.of.climate.and.non-climate.drivers)..For.climate.impacts,.identify.coping.ranges.and.critical.thresholds.(biophysical.and/or.behavioral)..estimate.likelihood.of.impact.(quantitatively.or.qualitatively,.as.feasible)..Prioritize.risks.and.determine.extent.of.uncertainties.
knowledge.of.the.probability.of.an.adverse.event.can.range.from.well.known.(e.g.,.the.likelihood.of.sea.level.rise.eventually.inundating.a.coastal.water.treatment.facility).to.probabilistic.(e.g.,.the.variability.of.streamflows.during.a.rainstorm).to.based.on.expert.judgment.(e.g.,.the.recurrence.period.under.climate.change.of.what.we.historically.defined.as.a.100.year.flood).to.relatively.unknown.(e.g.,.the.probability.of.decade-long.drought.under.climate.change)..the.level.of.uncertainty.associated.with.
Figure 8.3 Stage 1 – Objectives identification and system characterization
ObjectivesCharacterization
Analysis
Bottom Up (Threshold)
RiskAssessment
AdaptationOptions
Identification& Assessment
Top Down (Scenario)
Define driving climate and non-climate variables
Define driving climate and non-climate variables
Define thresholds Select climate change scenario
Define performancecriteria
Perform downscaling
Assess sensitivities to climate variables
Carry out hydrologic analysis
95
an.adverse.event.is.a.significant.factor.entering.into.the.choice.of.decision.making.strategies.and.tools.that.a.water.manager.might.utilize.as.discussed.below..Figure.8.4.gives.the.template.for.stage.2.
Stage 3 – Identify and evaluate options to manage risk
this.stage.includes.the.following.steps:
1..identify.(any).potential.adaptation.options.to.meet.‘success’.criteria.(and.are.within.thresholds.of.tolerable.risk)..A.list.of.adaptation.options.identified.in.the.review.of.the.bank’s.water.portfolio.is.given.in.chapter.6..Figure.8.5.shows.the.template.for.this.stage..A.typology.of.adaptation.options.adapted.from.burton.(1996).is.imbedded.in.this.template.
Figure 8.5 Stage 3 – Options identification and assessment to reduce risk
Determine systemresponse
Determine systemresponse
Determine systemresponse
ObjectivesCharacterization
Analysis
Share the loss
Bear the loss
Modify the events
Prevent the effects
Change use
Change location
Research
Education and behavioral change
On-site operations
Market-based
Institutional, administrative
Legislative, regulatory, financial
Structural, technologicalRisk
Assessment
AdaptationOptions
Identification& Assessment
Figure 8.4 Stage 2 – Assessment of risks
ObjectivesCharacterization
Analysis
Bottom Up (Threshold)
RiskAssessment
AdaptationOptions
Identification& Assessment
Top Down(Scenario)
Determine systemresponse
Determine systemresponse
Screening RiskAssessment
Qualitative RiskAssessment
Quantitative RiskAssessment
Determine consequences of the response
Assess consequencesof the response
Assess systemvulnerabilities
Assess impactsand vulnerabilities
Risk AssessmentMode
96
2..evaluate.adaptation.options.according.to.degree.of.uncertainty.and.established.rules.of.decision-making..in.all.circumstances,.look.for.no.regrets,.low.regrets.particularly.so.when.there.is.high.uncertainty..if.‘risk’.cannot.be.quantified,.can.also.use.approaches.for.decision-making.under.‘uncertainty’.(willows.and.connell,.2003)..the.options.of.‘do.nothing’.or.‘delay.decision’.are.possible..Avoid.climate.decision.errors.(over-adaptation,.under-adaptation.and.associated.maladaptation).
Considerations for the water sector
Susceptibility of water systems to climate change
A special class of diagnostic indicators identified as threshold-type or dynamic indicators are applied to the analysis of specific water resource systems or system design configurations..several.measures.of.the.robustness.of.water.systems.to.climate.change.have.been.proposed.that.permit.the.evaluation.of.a.specific.design.configuration.over.a.range.of.system.inputs.and.service.levels.(Hashimoto.et.al.,.1982a,.1982b)..each.indicator.is.based.on.the.probability.that.a.system,.characterized.by.a.given.set.of.design.parameters,.will.provide.the.intended.level.of.services.under.a.range.of.dynamic.inputs.and/or.demand.conditions..these.indicators.enable.an.analysis.that.extends.beyond.climatic.means.to.encompass.seasonal.and.interannual.variability,.serial.correlation.properties,.and.the.occurrence.of.extreme.events..the.measures.of.system.performance.are.defined.over.a.sequence.of.discrete.time.periods..within.each.period,.the.system.either.performs.(provides.an.acceptable.level.of.services).or.fails.to.do.so,.which.leads.to.the.following.complementary.metrics.
•.Reliability.is.how.often.a.system.fails.according.to.some.defined.criteria..it.is.also.defined.as.the.likelihood.that.services.are.delivered.(no.failure).within.a.given.period,.expressed.as.a.probability..High.probabilities.indicate.high.reliability.
•.Resiliency.is.how.quickly.a.system.recovers.from.a.failure
•.Robustness in.a.water.resources.system,.this.is,.conceptually,.the.extent.to.which.a.system.design.is.able.to.deliver.optimal.or.near-optimal.levels.of.service.over.a.range.of.demand.(input).and.supply.(resource).conditions..one.common.definition.of.robustness.emphasizes.flexibility:.the.ability.of.a.system.to.adapt.to.a.wide.range.of.operating.conditions.through.relatively.modest.and.inexpensive.levels.of.redesign,.refitting,.or.reoperation.
Adaptation Options for Water Systems
There are two perspectives from which water management under climate change can be considered. One focuses on potential adaptation options for reducing vulnerability and the other, on the decision-making process under uncertainty..each.of.these.provides.slightly.different.insights.into.the.question.of.‘when.and.how.should.water.managers.behave.differently’..there.is.a.common.thread.between.the.two.in.highlighting.that.traditional.approaches.in.many.cases.suffice,.although.there.are.also.instances.when.the.‘additional’.element.of.uncertainty.arising.from.climate.change.will.call.for.innovative.responses..A.brief.description.of.some.indicators.used.for.assessment.of.vulnerability.at.the.systems.level.is.given.in.box.8.2.
Potential options for adapting to climate change and variability in the water sector can be categorized into those that carry ‘no regrets’ and those that are ‘climate justified’. many.of.the.options.to.reduce.vulnerability.to.climate.variability.are.no.different.in.a.world.with.climate.change.than.they.are.in.a.world.without..these.include.demand.management.measures.
97
Box 8.2 Standardized indicators to assess the vulnerability of regions and systems to climate change
standardized.indicators.can.help.identify.regional.patterns.of.water.sector.vulnerability.to.changes.in.climate.
and.hydrology..using.indicators.to.diagnose.the.vulnerability.of.water.systems.increases.the.insight.of.water.
managers.into.how.climate.change.may.affect.the.functioning.of.infrastructure.design.and.the.efficacy.of.
alternative.management.practices,.and.can.be.used.proactively.to.diagnose.vulnerability.before.planning,.
financing,.and.implementing.a.water.project..vulnerability.to.climate.change.with.respect.to.water.systems.is.
strongly.related.to.three.factors:
•. Climate and hydrology:.the.status.of.regional.water.resources.–.mean,.trends,.and.variability.in.usable.
supplies;
•. Water demand, use, and depletion:.the.level,.structure.and.timing.of.abstractive.and.consumptive.
demand.for.water,.including.groundwater.
•. Water storage and management infrastructure,.which.mediate.between.hydro-climatic.conditions.and.
societal.demand.by.regulating.water.availability.in.space.and.time.
indicators.can.be.used.to.quantify.each.factor.discretely,.or.to.examine.the.overlay.of.supply,.demand.and.
management.infrastructure.within.a.given.region..one.example.of.a.supply-related.indicator.is.the.runoff ratio,.
defined.as.the.percentage.of.annual.precipitation.converted.to.surface.runoff.and.renewable.groundwater.
recharge..low.values.of.the.runoff.ratio.are.associated.with.high.vulnerability,.since.modest.changes.in.
temperature.or.precipitation.can.lead.to.large.relative.changes.in.available.water.supplies.
water.demand.vulnerability.indicators.place.emphasis.on.demand.relative.to.available.supply,.since.the.extent.
of.unused.capacity.provides.the.buffer.between.uncertain.future.supply.and.demand.conditions..one.indicator.
is.water crowding,.defined.as.the.number.of.people.per.million.cubic.meters.of.water.per.year.(vörösmarty.et.
al.,.2005)..A.crowding.index.greater.than.1,000.indicates.potential.scarcity..A.closely.related.indicator.is.the.
ratio.of.annual.withdrawals.to.renewable.water.supply,.identified.as.relative water demand.(vörösmarty.et.al.,.
2000)..these.concepts.have.been.extended.to.water use regimes..this.two-dimensional.indicator.distinguishes.
between.(i).undeveloped.or.natural.flow-dominated,.(ii).human.flow.dominated,.(iii).depleted.or.withdrawal.
dominated,.and.(iv).surcharged,.or.return-flow.dominated.regimes.
the.extent.to.which.water.storage.and.management.infrastructure.provides.a.buffer.for.societies.facing.climatic.
variability.or.change.is.an.important.component.of.vulnerability.and.resilience..A.simple.indicator.is.the.
storage-to-flow ratio,.defined.as.the.ratio.of.total.basin.storage.capacity.to.annual.renewable.discharge..A.
special.class.of.infrastructure-related.indicators.can.also.be.used.to.diagnose.the.vulnerability.of.specific.water.
resource.systems.or.system.design.configurations.to.alterations.in.supply.and/or.demand.conditions..they.are.
identified.as.reliability.(how.often.a.system.fails),.resiliency.(how.quickly.a.system.recovers.from.a.failure),.
vulnerability.(how.significant.are.the.consequences.of.a.failure),.and.robustness.(how.well.a.system.performs.
over.a.range.of.conditions)..these.indicators.are.described.in.Hashimoto.et.al..(1982a,.1982b).
to.increase.water.use.efficiency.and.productivity,.such.as.water-conserving.irrigation.technologies;.wastewater.recycling;.economic.incentives,.including.water.pricing;.and.the.encouragement.of.water.markets.that.move.water.to.high-valued.uses..they.also.include,.for.example,.measures.to.improve.early.warning.systems.and.risk-spreading.(e.g.,.disaster.insurance)..these.options.carry.‘no regrets’.in.that.they.would.go.a.long.way.in.confronting.the.climate.change.challenge,.yet.they.are.often.justifiable.even.under.current.conditions.of.variability..on.the.other.hand,.other.actions.might.be.justifiable.under.significant.change.in.climatic.variability..‘Climate justified’.actions.
98
include,.for.example,.constructing.new.infrastructure.(dams,.underground.storage,.irrigation.systems),.retro-fitting.existing.infrastructure,.changing.rules.of.operation,.tapping.new.sources.of.water.(e.g.,.desalinization),.water.transfers,.conjunctive.use.of.surface.and.groundwater,.innovative.demand.management,.etc.
The distinction between ‘no regrets’ and ‘climate-change justified’ options is important in near-term and long-term decision making..For.“no.regrets”.options,.uncertainties.in.climate.projections.are.to.a.large.extent.immaterial..by.definition,.these.actions.should.be.taken.in.order.to.meet.current.economic,.social.and.environmental.objectives,.but.they.also.serve.the.dual.purpose.of.reducing.vulnerabilities.to.future.climatic.conditions..it.is.in.the.realm.of.the.‘climate-justified’.that.water.managers.will.have.to.make.difficult.decisions.about.how.to.balance.the.political,.economic,.social.and.environmental.costs.of.action.versus.of.non-action,.given.an.uncertain.future..they.will.have.to.seek.and.apply.new.technologies.and.management.methods.to.ensure.that.system.reliability.is.maintained.under.changing.climate.circumstances..they.will.have.to.shift.their.thinking.on.how.to.plan.and.design.more.resilient.water.interventions..And,.they.will.need.to.develop.‘intelligent systems’.that.are.robust.in.the.sense.that.they.are.able.to.deliver.(near).optimal.levels.of.service.or.management.over.a.range.of.conditions,.including.through.relatively.modest.re-design,.retrofitting.or.re-operation..implicit.in.robustness.is.also.flexibility,.that.is,.the.ability.to.anticipate.and.react.to.a.wider.and.largely.unknown.range.of.future.climatic.conditions..All.of.these.actions.will.require.use.of.a.variety.of.new.and.innovative.tools.in.the.areas.of.economics,.finance,.institutions,.infrastructure.and.technology.
Categories of adaptation options
One of the most operational and often-used classifications of adaptations was introduced in the Intergovernmental Panel on Climate Change’s (IPCC’s) Third Assessment Report, based on Burton, et al. (1996)..below.is.an.updated.list,.revised.for.focus.on.the.water.sector.
•.No action. All.adaptation.measures.may.be.compared.with.the.baseline.response.of.“doing.nothing”.and.accepting.the.economic,.social,.environmental,.or.other.losses.caused.by.the.impacts.of.a.changing.climate..in.addition.to.providing.a.baseline.for.comparison,.“no.action”.occurs.where.the.costs.of.adaptation.are.considered.too.high.relative.to.benefits,.when.information.about.risks.is.lacking,.and.where.political.will.does.not.coalesce.to.address.adaptation,.among.other.situations.
•.Insurance. many.communities.face.some.risk.of.high.consequence.climate.events,.such.as.hurricanes,.floods,.tornadoes,.wildfires,.and.so.forth..one.way.to.hedge.against.these.risks.is.by.sharing.the.losses.among.a.wider.community..Private.or.public.insurance.mechanisms.can.share.risks.by.raising.revenues.from.a.large.insured.pool.to.provide.coverage.for.relief.and.reconstruction..insurance.includes.mechanisms.such.as.private.insurance.policies,.public.insurance.programs,.and.public.or.institutional.relief.efforts,.but.it.also.includes.a.variety.of.less.formal.mechanisms.such.as.reliance.on.church.and.non-governmental.organization.relief.efforts..insurance.is.typically.used.to.compensate.victims.for.losses.and.the.compensation.is.typically.used.to.repair.or.rebuild.damaged.structures.or.compensate.for.losses.that.cannot.be.repaired.or.rebuilt..note.that.when.insurance.regulations.or.policies.promote.an.increase.in.vulnerability.to.climate.events,.insurance.acts.instead.as.a.form.of.maladaptation..correcting.such.maladaptations.can.go.a.long.way.toward.reducing.vulnerability.and.protecting.people,.their.property,.and.their.environment.from.climate.risks..governments.can.also.serve.to.share.loss.by.providing.financial.and.other.aid.following.disasters..government.funds.can.be.used.to.rebuild.destroyed.property.or.compensate.victims.for.losses..this.tends.to.be.more.feasible.in.
99
larger.countries.(where.it.is.more.likely.that.an.adverse.event.only.strikes.a.small.portion.of.the.country’s.land.mass).and.wealthier.countries.which.have.more.financial.resources.to.devote.to.insurance.
•.Engineered protection. For.some.climate.impacts,.it.is.possible.to.engineer.protective.measures.that.reduce.the.risks.or.consequences.of.the.impact..examples.include.flood.control.works.(e.g.,.dams,.dikes,.levees,.sea.walls),.creating.fire.breaks.near.the.built.environment.to.reduce.fire.hazard,.and.building.new.or.improved.water.storage.facilities.to.hedge.against.drought..one.of.the.challenges.of.engineering.adaptations.to.climate.change.is.the.uncertainty.about.the.magnitude.of.change.in.variables.for.which.even.the.direction.of.change.is.unknown,.e.g.,.uncertainty.the.magnitude.of.temperature.increase,.sea.level.rise,.or.increase.in.intense.precipitation.
•.Managing the risk. A.frequently.used.set.of.adaptation.measures.involves.steps.to.manage.the.effects.of.climate.change..examples.include.improved.warning.systems.and.evacuation.centers.for.flood.or.cyclones,.and.diversifying.a.community’s.water.supply.portfolio.to.increase.resilience.to.drought..other.examples.might.include.limiting.development.in.vulnerable.areas.or.promoting.water.efficiency.measures.to.reduce.demand.for.water.and.vulnerability.to.droughts.
•.Change use. where.the.threat.of.climate.change.makes.the.continuation.of.a.climate.sensitive.activity.too.risky,.consideration.can.be.given.to.changing.its.use..governments.and.institutions.can.play.an.important.role.in.this.adaptation.option,.for.example,.by.regularly.revising.flood.zones.based.on.projections.of.altered.precipitation.regimes.or.sea.level.rise..As.a.result,.lands.once.slated.for.development.may.be.better.suited.as.buffers.for.floods.or.natural.floodplain.migration..government.subsidies,.regulations,.taxes,.and.other.incentives.can.play.a.large.role.in.facilitating.or.impeding.this.adaptation.option..For.example,.subsidies.for.specific.crops.may.provide.an.economic.disincentive.for.farmers.to.change.from.water.sensitive.crops.to.drought.tolerant.ones.in.areas.where.such.a.changed.use.makes.sense.
•.Change location. in.many.instances.the.location.of.physical.infrastructure.or.climate.sensitive.activities.is.the.primary.source.of.vulnerability.to.the.impacts.of.climate.change..For.example,.buildings.in.floodplains.or.along.the.coasts.will.face.increasing.vulnerability.to.floods.and.coastal.storms;.water.intensive.crops.grown.in.arid.environments.may.require.more.water.than.can.be.reliably.delivered.to.those.locations.in.places.where.drought.frequency.increases;.and.some.fisheries.may.migrate.northward.to.cooler.waters..settlements.or.economic.activities.may.need.to.be.relocated.in.response.to.such.changes..this.adaptation.can.carry.significant.to.extremely.high.costs,.but.may.be.the.unavoidable.adaptation.of.last.resort..the.need.to.abandon.some.areas.has.been.advocated.by.many,.including.sachs.(2008).
•.Research..For.many.adaptations,.improved.understanding.of.climate.change.and.its.impacts.is.needed..more.geographically.and.temporally.precise.climate.projections.can.aid.adaptation.as.it.could.reduce.uncertainties.about.the.direction.and.magnitude.of.change.in.key.climate.variables.such.as.precipitation..many.potential.impacts.of.climate.change.are.inadequately.understood..Adaptation.itself.is.not.well.understood,.particularly.how.individuals.and.societies.will.respond.to.changing.climate..this.is.not.an.option.for.individual.water.managers,.but.the.need.for.research.needs.to.be.communicated.to.the.research.community.
•.Education and behavioral change. Another.type.of.adaptation.focuses.on.changing.the.practices.of.individuals.or.institutions..this.often.involves.the.dissemination.of.knowledge.through.education.and.public.information.campaigns..one.example.is.waste.of.water,.for.example,.by.leaving.taps.on.or.not.attending.to.leaks..changing.behavior.can.be.fostered.through.education.campaigns,.appropriate.regulatory.instruments,.pricing,.incentives,.taxes,.and.subsidies.or.the.removal.of.such.instruments.if.they.impede.adaptation.
100
Class of projects for which risk-based analysis would be particularly essential
Climate change will affect most water systems to some degree..However,.some.water.services.or.resources.by.their.very.nature.are.more.vulnerable.to.climate.change.than.others..For.example,.small.or.distributed.water.supply.systems.that.can.easily.make.incremental.changes.at.low.cost.are.vulnerable.to.climate.change,.but.may.face.less.exposure.to.changes.in.climate,.may.be.less.sensitive.to.climate.changes,.or.may.have.sufficient.adaptive.capacity.to.manage.those.changes..the.systems.below,.however,.are.particularly.vulnerable.and.special.care.should.be.taken.to.flag.such.water.investments.for.risk-based.decision.making..these.systems.would.likely.be.designed.differently.if.climate.change.were.taken.into.account,.and.failing.to.do.so.would.likely.cause.significant.economic.loss.(Hobbs,.et.al.1997).
•.Highly capitalized or unique projects:.Any.project.that.requires.a.very.large.investment.or.has.a.high.opportunity.costs,.such.as.most.infrastructure.systems.or.large.watershed.protection.projects,.needs.to.include.consideration.of.climate.change.because.the.stakes.of.failing.to.accurately.assess.risk.are.simply.too.high,.often.on.the.order.of.many.millions.of.dollars.
•.Engineering structures with long lifetimes:.water.infrastructure.projects.often.have.lifetimes.of.50.years.or.more..the.best.available.science.indicates.that.climate.changes.may.not.be.significant.for.planning.purposes.over.just.a.few.years,.but.over.the.course.of.many.decades,.changes.in.climate.are.expected.to.manifest.in.ways.significant.for.planning.purposes.
•.Multi-purpose infrastructure systems:.some.systems.serve.multiple.purposes,.such.as.dams.that.provide.water.supply.storage.and.flood.control..the.management.of.such.systems.often.involves.tradeoffs.between.these.purposes.(e.g.,.how.much.water.to.keep.in.a.reservoir.is.driven.in.part.by.ensuring.enough.additional.capacity.to.capture.flood.waters.should.a.flood.occur)..because.these.systems.must.balance.risk.related.to.multiple.purposes,.it.increases.the.importance.of.incorporating.climate.change.considerations.
•.Long-lived benefits and costs:.similarly,.any.project.whose.benefits.or.costs.are.spread.out.over.a.long.timeframe.may.need.to.incorporate.potential.future.changes.in.climate.to.see.how.it.affects.those.benefits.or.costs..this.could.radically.alter.the.justifiability.of.a.water.project.
•.Systems susceptible to climate anomalies or extreme events:.Any.water.investment.or.management.regime.that.can.be.significantly.affected.by.floods,.droughts,.hurricanes,.or.other.climate.anomalies.needs.to.consider.the.potential.increase.in.risks.from.climate.change.because.these.extreme.events.account.for.the.bulk.of.climate-related.damages.to.water.projects..small.increases.in.the.frequency.or.severity.of.these.events.can.lead.to.exponential.increases.in.damages.
•.Urban water supply:.urban.water.demand.is.increasing.in.most.places,.but.it.can.be.managed.on.both.the.demand.and.the.supply.side..because.of.the.multiple.adaptation.possibilities.(e.g.,.leak.reduction,.metering,.eliminating.unauthorized.taps),.urban.water.supply.provides.an.excellent.opportunity.to.relieve.stress.on.basin-wide.water.systems.and.thus.makes.the.entire.system.less.vulnerable.
•.Water systems facing non-climate stress:.many.water.systems.are.vulnerable.to.non-climatic.trends.such.as.urbanization,.deforestation,.changes.in.agricultural.or.industrial.water.demands,.and.so.on..because.these.water.systems.become.more.stressed,.they.also.become.more.vulnerable.to.changes.in.hydrology.and.hence.climate.change.
Identification of water systems or projects that merit consideration of risk-based decision making involve a two step process..First.we.recognize.the.need.to.incorporate.risks.of.future.events.into.our.planning.decisions..next.we.must.figure.out.what.kinds.of.remedial.action.can.be.taken.to.reduce.those.risks,.and.what.the.costs.and.benefits.of.those.risk.management.options.
101
may.be..the.term.adaptation.refers.to.policy.actions.intended.to.reduce.the.vulnerability.of.systems.to.climate.variability.and.change.
assessing risk: application to multi-purpose infrastructure projects26
Depending on the class of project and the expected risk and consequences of exposure to climate change, the level of analysis varies..As.an.illustration.of.the.application.of.the.risk-based.decision.making,.the.process.for.assessment.of.risk.associated.with.multi-purpose.infrastructure.is.presented.here..this.multi-purpose.example.focuses.on.elements.of.stages.2.and.3.of.the.risk-based.assessment.framework.described.above.
Hydrologic drivers for multi-purpose hydraulic infrastructure
The primary driver of climate change impacts on dams and reservoirs is temperature..current.climate.models.suggest.that.the.effects.of.temperature.increases.are.felt.throughout.the.climatic.regime,.leading.to.hydrologic.changes.(e.g.,.seasonal.redistribution.and.duration.of.rainfall).and.other.related.impacts..these.hydrologic.changes.are.manifested.as.periods.of.increased.rainfall.or.floods,.as.well.as.periods.of.reduced.rainfall.or.drought..in.addition.to.precipitation.effects,.increased.temperatures.are.impacting.glacier.and.snowmelt.patterns,.while.also.creating.more.extreme.hurricane.or.typhoon.conditions.with.associated.high.winds..A.representative.list.of.temperature,.rainfall,.and.wind.related.effects.that.may.impact.a.multipurpose.hydraulic.infrastructure.is.provided.in.box.8.3.
While acknowledging the myriad effects on multi-purpose infrastructures from all of the above drivers, this assessment of climate change impacts is focused on the primary hydrologic drivers of vulnerability as described earlier in this report:
•.Annual.Average.Precipitation;•.Precipitation.extremes;•.glaciers.and.snow;•.sea.level;•.evapotranspiration;•.soil.moisture;•.runoff.and.river.discharge.
Project components
The project components are first described and assessed in terms of their sensitivity to the major hydrologic climate change drivers. the.risk-based.analysis.framework.is.then.developed.in.a.matrix.format.to.characterize.the.severity.or.sensitivity.of.climate.change.impacts.on.each.component..the.analysis.framework.is.then.applied,.using.a.defined.methodology.for.evaluation.and.scoring.of.impacts,.to.obtain.an.overall.picture.of.project.vulnerability.to.climate.change.
•.dam.structure;•.reservoir.storage;
26 ThismethodologyisdescribedinmoredetailinthebackgroundreportWaterandClimateChange:AssessmentofClimateChangeImpactsonMultipurposeInfrastructure
102
•.service.&.Auxiliary.spillways;•.intake.works;•.Hydropower.Plants;•.low-level.outlet.works;•.tunnels;•.open.channels.
In order to prioritize and justify design accommodations to adapt to climate change, it is desirable to have a logical, repeatable methodology..this.is.particularly.important.for.quantifying.the.risks.related.to.the.various.dam.and.reservoir.project.components.exposed.to.climate.change.drivers,.and.then.determining.the.most.attractive.adaptation.strategies.for.
Box 8.3 Potential impact some of key hydrologic drivers
Temperature
•. increased.mean.ambient.temperatures;
•. increased.peak.temperatures;
•. increased.evaporation;
•. increased.humidity.(if.accompanied.by.a.generally.wetter.climate);
•. increased.snowmelt.and.retreating.of.glaciers;
•. increased.vegetation.(if.accompanied.by.generally.higher.rainfall);
•. loss.of.vegetation.(if.accompanied.by.periods.of.prolonged.drought);
•. increased.desiccation.(if.accompanied.by.periods.of.prolonged.drought);
•. increased.insect.populations;
•. increased.methane.production.in.reservoirs.from.rotting.vegetation;.and
•. increased.stratification.and.water.quality.variations.in.reservoirs.
Rainfall
•. increased.peak.runoff.and.river.discharge;•. increased.reservoir.yields.(in.the.case.of.prolonged.wetter.conditions);•. reduced.reservoir.yields.(in.case.of.prolonged.drought.periods);•. Higher.river.floods;•. Higher.localized.storm.intensities;•. increased.vegetation.(in.case.of.prolonged.wetter.conditions);•. increased.sediment.(in.the.case.of.prolonged.drought.periods.that.can.desiccate.watershed.soils);•. increased.debris.flows;•. increased.lightning.incidents.(in.the.case.of.high.energy.storms);.and•. Prolonged.solar.exposure.(in.the.case.of.prolonged,.reduced.cloud.cover).
Wind
•. increased.prolonged.wind.speeds;
•. Associated.increases.in.the.wave.heights.on.reservoirs;
•. Associated.increased.“seiche”.(wind.set-up).effects.on.reservoirs;
•. increased.gust.speeds;
•. Associated.increased.structural.wind.loading.on.exposed.structures;
•. greater.amounts.of.atmospheric.dust;.and
•. greater.amounts.of.windblown.debris.
103
implementation..For.a.given.exposure,.the.risks.are.identified.as.a.function.of.criticality,.sensitivity.and.adaptability.of.each.component.
A risk-based approach to evaluating the sensitivity of multi-purpose infrastructure components to climate change begins with assessing the risk factors (or attributes) that are important to defining the component’s response to a climate-change induced stressor..these.risk.attributes.can.be.organized.in.three.indicative.categories.as.follows:
Criticality•.likelihood.of.Failure•.consequence.of.Failure
sensitivity•.robustness•.resilience
adaptability•.Adaptive.capacity•.cost.of.Adaptation
Mapping the climate change impact onto project components
The component risk analysis starts with mapping the project components to their primary climate change impact drivers..in.order.to.frame.the.criticality.of.a.given.component,.the.major.drivers.of.climate.change.impacts.on.multi-purpose.infrastructures.are.mapped.against.the.principal.structural.components.of.the.project.
while.the.matrix.on.table.8.1.indicates.that.there.are.multiple.drivers.acting.upon.a.given.component,.a.methodology.for.identifying.the.“alpha”.driver.that.governs.the.design.or.configuration.of.the.component.is.needed..to.do.so,.it.is.necessary.to.delve.more.deeply.into.these.relationships.in.order.to.assess.the.vulnerability.of.the.components.to.climate.change.impacts..this.component.assessment.represents.an.essential.initial.step.in.ultimately.making.valid.recommendations.for.adaptive.measures.to.manage,.reduce,.or.eliminate.these.impacts.
Scoring of component risk
Each component is scored according to the risk attribute within each indicator category..An.example.of.the.scoring.range.and.scale.is.given.in.table.8.2.
Each major project component is scored for each indicator..this.results.in.a.ranking.in.each.category.for.each.component..this.assessment.can.first.be.done.on.a.generic.basis,.using.expert.knowledge.of.the.planning.and.design.process.for.a.dam.or.reservoir.project..it.is.then.further.refined.and.quantified.for.a.particular.project,.as.further.study.and.available.information.warrant..the.scoring.process.involves.three.basic.steps:
•.Assess.and.score.criticality,.vulnerability,.and.adaptability.of.the.component;•.Apply.weighting.factor.in.each.category.in.order.to.reflect.the.relative.importance.of.the.
category.in.the.decision.process;.and•.Prioritize.components.on.which.to.focus.based.on.the.highest-to-lowest.scores.obtained.
104
Table 8.1 Matrix of hydrologic drivers and infrastructure components
Driver of Impact
Dam
Structure
Reservoir
Storage
Service &
Auxiliary
Spillways
Intake
Works
Hydropower
Plants
Low-Level
Outlet
Works Tunnels
Open
Channel
Average Annual
Precipitation (AP)
X X X X X X
Precipitation
Extremes (EP)
X X X X X X X X
Glaciers and Snow
(GS)
X X X X X X X X
Sea Level (SL)
Evapotranspiration
(ET)
X X
Soil Moisture (SM) X X X
Runoff and River
Discharge (RR)
X X X X X X X X
Table 8.2 Scoring by category for each component
Indicator Category
Key to Scoring
(based on 10 point scale)* Weight
Criticality likelihood.of.Failure
low.=.1;.med.=.3;.High.=.5
1*
consequence.of.Failure:
low.(affects.reliability/availability).=.1;
med.(affects.performance).=.3;
High.(affects.safety).=.5
Sensitivity robustness**:.low.=.5;.med.=.3;.High.=.1 1*
resilience**:.low.=.5;.med.=.3;.High.=.1
Adaptive.capacity.(Planned.Projects)**:.low.=.5;.med.=.3;.High.=.1 1*
Adaptability Adaptive.capacity.(existing.Projects):.low.=.1;.med.=.3;.High.=.5
cost.of.Adaptation.(Planned.Projects):.low.=.1;.med.=.3;.High.=.5
cost.of.Adaptation.(existing.Projects)**:.low.=.5;.med.=.3;.High.=.5
* scoring.scale.and.weight.may.be.varied.as.needed.** score.is.inversely.proportional.to.the.attribute..the.highest.total.score.is.assigned.to.the.project.component.that.as.the.highest.criticality,.highest.vulnerability.(i.e.,.least.robust.and.resilient),.and.lowest.adaptability.(i.e.,.low.adaptive.capacity.and.highest.cost.of.adaptation).
105
For a given project analysis, the scoring for the risk attributes in each category should be done on a consistent and replicable basis that does not introduce a bias into the analysis..the.weighting.factors,.on.the.other.hand,.should.be.varied.to.test.the.sensitivity.of.the.category.weights.on.the.prioritization.of.the.actions..the.dam.and.reservoir.project.component.risk.analysis.enables.means.to.identify.the.project.features.that.are.the.most.sensitive.to.climate-induced.changes.in.hydrologic.conditions..the.following.sequence.for.application.of.the.assessment.framework.defines.a.methodology.for.evaluating.the.impacts.of.climate.change.on.multi-purpose.infrastructures.on.a.logical,.replicable.basis.
Assessment of project components most at risk
The results of the scoring exercise provide information on the components which are most critical, most sensitive, and least adaptable as priority components for early attention in the planning and design stages of a proposed project..Analysis.of.existing.and.future.projects.differ.in.that.there.is.more.opportunity.for.planning.and.designing.against.vulnerabilities.and.providing.means.of.adaptation,.than.for.existing.projects..table.8.3.provides.a.generic.matrix.template.for.assessment.and.ranking.for.multi-purpose.infrastructure.projects..opportunities.and.strategies.for.adaptation.of.multi-purpose.infrastructure.components.to.climate.change.is.outlined.in.Annex.c.
Table 8.3 Scoring matrix template
Component Criticality Score Sensitivity Score
Adaptability
Score Total Score Priority
dam.structure
reservoir.storage
spillways
intake.works enter.score.for.each.component.and.
under.each.category.
sum.scores.and.rank.
Caution:.to.be.used.to.gain.insight.
and.in.conjunction.with.non-numerical.
assessments.
Hydropower.
Plants
low.level.outlet.
works
tunnels
open.channels
Top Component
in Category
106
107
CHaPTer 9: nexT sTePs: an agenda on ClimaTe CHange for THe waTer PraCTiCe
Insight into the various dimensions of water and climate change has identified the gaps and guides the next steps..As.the.world.bank.water.agenda.mainstreams.adaptation.to.the.impact.of.climate.change,.the.questions.raised.at.the.beginning.of.this.report.continue.to.remain.valid.and.should.be.an.integral.part.of.the.ongoing.work.at.the.water.anchor.in.support.of.the.regions..these.questions.are:.(i).what.are.the.impacts.of.climate.variability.and.change.on.water.systems,.both.natural.and.engineered;.(ii).what.are.adaptation.strategies.to.reduce.vulnerability.of.water.systems.to.these.impacts;.and.(iii).how.can.the.bank.assist.client.countries.in.making.informed.decisions.regarding.adaptation.options.in.their.water.investments?.in.relation.to.the.latter.question,.it.is.obvious.that.factors.other.than.climate.change.also.exert.pressure.on.water.resources..in.some.cases.these.factors.may.dominate.climate.change,.in.other.cases.climate.change.induced.pressure.may.dominate..in.all.cases,.informed.decisions.regarding.water.investments.have.to.take.into.account.both.the.climate.and.the.non-climate.induced.pressures.
below.the.report.briefly.describes.how.this.flagship.effort.has.provided.tools.to.make.better.informed.decisions.regarding.water.investments.and.the.proposed.areas.of.activity.to.be.carried.out.in.the.future.by.the.water.anchor.in.support.of.the.regions.to.provide.a.basis.for.continuous.improvements.in.decision.making.in.conjunction.with.the.continuous.expansion.of.information.and.knowledge.available.about.the.effects.of.climate.change.
Continue to strengthen the analytical foundation
Improve the hydrologic projections and exposure assessment methodology for application in project preparation. A.critical.step.in.the.bank’s.effort.in.addressing.climate.change.adaptation.is.an.agreed.set.of.future.climate.change.scenarios.for.each.region.to.ensure.consistency.and.compatibility.across.work.in.all.sectors..this.flagship.effort.has.provided.projections.of.the.hydrologic.drivers.for.water.investment..Hydrologic.variability.and.climate.change.signals.have.been.translated.to.indicators.with.quantitative.measures.of.magnitude.and.variability..the.next.step.would.be.to.make.them.readily.available.to.the.regional.staff.for.use..this.will.require.additional.analysis.of.the.projections,.as.well.as.development.of.a.user.interface.(or.adoption.of.an.existing.one).to.facilitate.use..At.the.same.time,.a.plan.shall.be.made.for.updating.the.projections.of.hydrologic.drivers.(and.their.indicators.with.quantitative.measures.of.magnitude.and.variability).for.water.investments.on.a.regular.basis.(say.every.2.to.3.years).as.improved.and.additional.climate.change.scenarios.become.available.
Improve the procedure for risk-based approach to adaptation options assessment and decision making. most.conventional.interventions.in.the.water.sector.are.not.likely.to.be.effective.under.increased.conditions.of.variability.and.uncertainty.because.they.have.been.predicated.on.the.assumption.of.hydrologic.stationarity..the.flagship.report.has.considered.the.issue:.how.to.deal.with.projections.in.a.world.where.“stationarity.is.dead”..the.report.strongly.argues.for.the.necessity.for.incorporation.of.a.formal.risk-based.approach.in.water.investments..A.framework.for.risk-based.analysis.is.proposed.in.the.report.together.with.an.example.of.how.such.a.framework.may.be.applied.to.the.bank’s.project.cycle..the.next.step.would.be.to.further.expand.and.formalize.this.process.to.allow.for.explicit.characterization.of.risks,.options,.and.management.of.risks..the.approach.should.incorporate.unfolding.uncertainties.over.time,.and.account.for.the.performance.of.adaptation.options..this.requires.
108
increased.capability.to.understand,.to.quantify,.and.manage.risk.in.an.environment.of.increased.uncertainty.
Improve decision making by expanding economic considerations to explicitly include climate change..the.main.focus.of.this.flagship.effort.was.to.understand.and.characterize.the.behavior.of.the.hydrologic.drivers.that.can.impact.design.and.operation.of.various.water.systems.and.investments..the.current.work.sets.the.stage.for.and.provides.the.needed.information.for.a.risk-based.approach.to.the.assessment.of.the.economics.of.water.investment.
In any investment decision, economics figure prominently. Two future areas of work are suggested:
1..it.is.proposed.at.the.country,.river.basin.or.even.sub-river.basin.level.to.prepare.assessments.of.the.cost.of.adaptation..different.interventions.will.have.different.costs.and.in.order.to.focus.on.cost-effective.interventions.early.in.the.project.cycle.it.will.be.valuable.to.have.an.assessment.of.the.cost.of.adaptation.to.address.climate.change.induce.and.non-climate.change.induced.water—related.risks.(whether.flooding,.water.scarcity.or.other)..work.is.already.under.way.to.assess.marginal.cost.curves.for.alleviation.of.water.scarcity..similar,.but.country.or.water.basin.specific.work,.which.also.considers.the.effects.of.pricing.and.other.institutional.policies,.may.contribute.to.focus.on.cost-effective.interventions.and.may.provide.very.useful.guidance.for.dPl.type.interventions..the.division.of.responsibilities.between.the.water.Anchor’s.role.to.provide.methodological.guidance.and.the.responsibilities.of.the.bank’s.regions.and.country.offices.for.implementation.need.careful.consideration.in.designing.such.work.
2..it.is.proposed.to.initiate.review.of.the.current.methodology.for.project.economic.analysis.and.develop.methodology.for.incorporation.of.climate.change.impacts.at.the.project.level..specific.areas.of.focus.would.be.i).economic.valuations.and.other.metrics.for.ranking.the.potential.impacts.of.climate.change,.and.ii).approaches.to.comparison.of.costs.and.benefits.over.time,.risk.attitudes,.and.distributional.concerns.
Finally, in the future work is needed on the impact of climate change on social and economic development..recognizing.that.climate.change.has.real.effects.on.people’s.livelihoods,.recognizing.that.these.effects.make.themselves.felt.mainly.via.the.water.cycle,.and.recognizing.that.by.analyzing.the.cumulative.and.cross-sectoral.impacts.it.is.possible.to.gain.an.understanding.of.where.the.bank.may.most.cost-effectively.support.countries.in.their.own.efforts.to.improve.the.livelihoods.of.poor.people,.work.has.been.proposed.(for.example.by.the.china.country.office).to.study.the.impact.of.climate.change.on.social.and.economic.development.at.the.country.level..it.would.be.useful.to.expand.such.work.to.many.bank.client.countries.and.the.water.Anchor.may.contribute.by.providing.back.ground.material.including.but.not.limited.to.typologies.of.countries.and.check.lists.of.impacts.and.dynamics.to.be.considered.
incorporate hydrologic variability and climate resiliency considerations in bank operations
Guidelines for incorporation of hydrologic variability and climate change in project preparation. this.would.include.use.of.the.improved.methodology.above.to.broadening.the.risk-based.framework.to.include.all.water.systems..A.related.useful.product.would.be.a.response.matrix.of.the.appropriate.coping/adaptation.strategies.to.the.hydrologic.projections.by.water.system,.usage.and.by.climate-sub-region..development.of.a.systematic.process.for.incorporation.
109
of.response.matrix.in.the.project.cycle.would.help.streamline.the.work.of.task.managers..A.series.of.case.studies.to.illustrate.the.process.would.also.be.useful.
Develop practitioners notes for feasibility studies, planning and design studies for infrastructure projects. these.notes.should.address.planning.and.design.issues.within.a.basin-wide.context,.rather.than.as.individual.projects..this.would.help.with.optimization.of.infrastructure.design.for.water.storage,.supply,.or.hydropower.taking.into.account.climate.change.factors..the.case.studies.carried.out.as.part.of.the.Flagship.study.can.be.beneficial.in.this.regard..A.note.on.methodology.for.evaluating.projects.on.a.component.(or.water.system).level,.for.criticality.to.project.function,.vulnerability.to.climate.change.impacts,.and.adaptability.in.the.face.of.climate.change,.could.be.helpful.to.task.managers.
Implications of climate change in managing ecosystems..the.objective.of.this.activity.would.be.to.first.better.understand.the.climate.change.impacts.on.aquatic.ecosystem.functions.and.resiliency.and.incorporate.a.structured.approach.for.factoring.them.into.integrated.water.resources.planning,.design,.and.operation.decisions.
the.guideline.developed.for.this.purpose.should.address.both.environmental.flow.and.water.quality.implications.of.climate.change..it.will.review.how.ecosystem.services.will.be.affected.by.the.changes.in.flow.volumes,.timing.and.quality.due.to.both.natural.climate.variability.and.climate.change..the.implications.of.altered.demand.for.agriculture,.municipal.and.industrial.supply.due.to.climate.change.on.environmental.services.should.be.discussed..the.various.impacts.of.climate.change.on.water.quality.in.rivers.(e.g.,.sediment.loads),.lakes.and.reservoirs.(e.g.,.temperature,.dissolved.oxygen,.mixing,.stratification).and.groundwater.(e.g.,.saltwater.intrusion.in.coastal.aquifers).and.their.implications.on.magnifying.pollution.impacts,.including.on.human.health.and.ecosystem.health.should.be.defined..ecosystem.implications.of.adaptation.responses.including.supply.side.options.and.demand.management,.including.reoperations.should.be.described.
Water and carbon footprint of water investments. As.part.of.project.planning.and.implementation,.an.analysis.of.the.carbon.and.water.footprint.of.intervention.could.provide.insight.into.the.sustainability.of.the.proposed.action.
strengthen bank expertise on water and climate change
Bank staff experience and expertise..climate.change.has.become.a.major.area.of.focus.at.the.bank,.drawing.a.great.deal.of.attention.at.the.corporate.and.the.regional.levels..many.water.professionals.are.engaged.in.climate.change.work.as.evidenced.by.the.increasing.volume.of.climate-related.lending.and.non-lending.activities,.as.well.as.seminars,.workshops,.and.briefings.to.management..with.some.exceptions,.most.of.the.bank.water.staff.lack.practical.experience.in.climate.change.and.hydrologic.variability.related.to.water.resources.management.and.water.services.delivery.systems..much.of.the.current.expertise,.information.and.data.related.to.the.impact.of.climate.change.and.adaptation.strategies.exist.outside.of.the.bank..For.the.bank.to.position.itself.at.the.forefront.of.climate.change.work.in.the.water.sector,.it.is.proposed.that.in-house.expertise.be.strengthened.and.to.the.degree.appropriate,.complemented.by.external.expertise.through.easily.accessible.mechanisms..the.following.specific.actions.are.suggested.as.a.starting.point.
•.expand.the.external.technical.team.of.experts.and.high-level.advisory.group.beyond.hydrologic.drivers.to.include.economics,.and.environmental/social.aspects.of.water.and.climate.change.
110
•.Formalize.partnerships.with.leading.international,.academic,.and.research.organizations.that.are.reputable.in.the.field.of.climate.change.in.the.water.sector.
•.develop.and.implement.programs.for.building.capacity.based.on.assessment.of.the.knowledge.and.experience.of.bank.staff.and.identified.gaps.
•.engage.the.newly.established.water.resources.management.thematic.group.to.investigate.the.operational.implications.of.incorporating.climate.change.adaptation.options.in.water.investments.
111
10. referenCes
Alcamo,.j..and.t..Henrichs..2002..critical.regions:.A.model-based.estimation.of.world.water.resources.sensitive.to.global.changes..Aquatic.sciences.64:.352–362.
Arnell,.n.w..2003..effects.of.iPcc.sres.emissions.scenarios.on.river.runoff:.A.global.perspective..Hydrology and Earth System Sciences.7(5):.619–641.
Arnell,.n.w..2004..climate.change.and.global.water.resources:.sres.emissions.and.socio-economic.scenarios..Global Environmental Change.14:.31–52.
bates,.b.c.,.Z.w..kundzewicz,.s..wu.and.j.P..Palutikof,.eds.,.2008:.climate.change.and.water..technical.Paper.of.the.intergovernmental.Panel.on.climate.change,.iPcc.secretariat,.geneva,.210.pp.
berry,.P.,.Paterson,.j.,.cabeza,.m..et.al..2008..mitigation.measures.and.adaptation.measures.and.their.impacts.on.biodiversity..minimisation.of.and.Adaptation.to.climate.change:.impacts.on.biodiversity.(mAcis)..oxford.university,.320pp.
bramer,.d..wojtowicz,.d.,.Hall,.s..(2008):.university.of.illinois.ww2010.Project..(Available.from:.http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hyd/smry.rxml).
broadleaf.and.mjA..2006..climate.change.impacts.&.risk.management:.A.guide.for.business.and.government..broadleaf.capital.international.and.marsden.jacob.Associates..Australian.greenhouse.office,.department.of.the.environment.and.Heritage,.canberra.Ago,.pp..19–21.
burton,.i..1996..“the.growth.of.Adaptation.capacity:.Practice.and.Policy.”.in:.j.b..smith,.n..bhatti,.g..menzhulin,.r..benioff,.m..budyko,.m..campos,.b..jallow,.and.F..rijsberman.(eds.)..Adapting.to.climate.change:.Assessments.and.issues..new.york:.springer..pp..55–67.
döll,.P.,.and.m..Florke..2005..global-scale.estimation.of.diffuse.groundwater.recharge..Frankfurt.Hydrology.Paper.3..institute.of.Physical.geography..Frankfurt.university,.Frankfurt.
döll,.P..2009..vulnerability.to.the.impact.of.climate.change.on.renewable.groundwater.resources:.a.global-scale.assessment..environ..res..lett.,.4,.036006.(12pp).
Frederick,.k.,.d..major,.and.e..stakhiv..1997..water.resources.Planning.Principles.and.evaluation.criteria.for.climate.change:.summary.and.conclusions..Climatic Change.37:.291–313.
giannini.A.,.m..biasutti,.i..m..Held,.and.A..H..sobel..2008..A.global.perspective.on.African.climate..climatic.change.90.(4):.359-383.
Hashimoto,.t.,.d.P..loucks,.and.j.r..stedinger..1982a..robustness.of.water.resources.systems..Water Resources Research.18(1):.21–26.
Hashimoto,.t.,.j.r..stedinger,.and.d.P..loucks..1982b..reliability,.resiliency.and.vulnerability.criteria.for.water.resource.system.performance.evaluation..Water Resources Research.18(1):14–20.
Hazen,.A..1914..storage.to.be.provided.in.impounded.reservoirs.for.municipal.water.supply..Trans. ASCE.77:1539–1640.
Hobbs,.b.F.,.P.t..chao,.and.b.n..venkatesh..1997..using.decision.Analysis.to.include.climate.change.in.water.resources.decision.making..Climatic Change.37:.177–202.
igrAc..2004..degree.of.groundwater.development..map.provided.on.the.global.groundwater.information.system..Available.online:.http://igrac.nitg.tno.nl/ggis_map/start.html.
iPcc..2001..climate.change.2001:.the.scientific.basis,.j.t..Houghton,.y..ding,.d.j..griggs,.m..noguer,.P.j..van.der.linden,.d..xiaosu,.and.k..maskell.(eds.)..intergovernmental.Panel.on.climate.change..cambridge.university.Press,.cambridge,.uk.and.new.york,.usA.
iPcc..2007a..summary.for.policymakers..in.climate.change.2007:.the.Physical.science.basis..Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change,.s..solomon,.d..Qin,.m..manning,.Z..chen,.m..marquis,.k.b..
112
Averyt,.m..tignor.and.H.l..miller.(eds.)..cambridge.university.Press,.cambridge,.uk.and.new.york,.usA.
iPcc..2007b..climate.change.2007:.synthesis.report..contribution.of.working.groups.i,.ii.and.iii.to.the.Fourth.Assessment.report.of.the.intergovernmental.Panel.on.climate.change.[core.writing.team,.Pachauri,.r.k.and.reisinger,.A..(eds.)]..iPcc,.geneva,.switzerland,.104.pp.
iPcc..2007c..climate.change.2007:.the.Physical.science.basis..contribution.of.working.group.i.to.the.Fourth.Assessment.report.of.the.intergovernmental.Panel.on.climate.change.[solomon,.s.,.d..Qin,.m..manning,.Z..chen,.m..marquis,.k.b..Averyt,.m.tignor.and.H.l..miller.(eds.)]..cambridge.university.Press,.cambridge,.united.kingdom.and.new.york,.ny,.usA.
kabat,.P.,.van.schaik,.H.,.Appleton,.b..2003..climate.changes.the.water.rules:.How.water.managers.can.cope.with.today’s.climate.variability.and.tomorrow’s.climate.change..dialogue.on.water.and.climate..the.netherlands.
kirshen,.P.,.m..mccluskey,.r..vogel,.and.k..strzepek..2005..global.analysis.of.changes.in.water.supply.yields.and.cost.under.climate.change:.A.case.study.in.china..Climatic Change.68:.303–330.
kundzewicz,.Z.w.,.l.j..mata,.n.w..Arnell,.P..döll,.P..kabat,.b..jiménez,.k.A..miller,.t..oki,.Z..sen.and.i.A..shiklomanov,.2007:.Freshwater.resources.and.their.management..climate.change.2007:.impacts,.Adaptation.and.vulnerability..Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change,.m.l..Parry,.o.F..canziani,.j.P..Palutikof,.P.j..van.der.linden.and.c.e..Hanson,.eds.,.cambridge.university.Press,.cambridge,.uk,.173–210.
mcmichael,.A..j..and.A..Haines,.1997..global.climate.change:.the.potential.effects.on.health.bmj.315:.805–809.
milly,.P.c.d.,.k.A..dunne.and.A.v..vecchia..2005..global.pattern.of.trends.in.streamflow.and.water.availability.in.a.changing.climate..nature.438(17):.347–350.
milly,.P.c.d.,.j..betancourt,.m..Falkenmark,.r.m..Hirsch,.Z.w..kundzewicz,.d.P..lettenmaier,.and.r.j..stouffer..2008..Science.319:.573–574.
mogaka,.H,.s..gichere,.r..davis.and.r..Hirji..2006..climate.variability.and.water.resources.degradation.in.kenya..world.bank.working.Paper.no..69..world.bank:.washington,.dc.
nrc..1983..risk.Assessment.in.the.Federal.government:.managing.the.Process..u.s..national.research.council..u.s..government.Printing.office,.washington,.dc.
nrc..1994..science.and.judgment.in.risk.management..u.s..national.research.council..u.s..government.Printing.office,.washington,.dc.
raskin,.P.,.P..gleick.,.P..kirshen,.g..Pontius,.and.k..strzepek..1997..Water Futures: Assessment of Long-Range Patterns and Problems, Comprehensive Assessment of Freshwater Resources of the World..stockholm.environment.institute,.stockholm.
sachs,.j..2008..commonwealth:.economics.for.a.crowded.Planet..Penguin.Press.smakhtin,.v.,.c..revenge,.P..doll,.and.r..tharme..2003..Putting the Water Requirements of
freshwater into the Global Picture of Water Resources Assessment..iwmi,.colombo.smit,.b.,.Pilifosova,.o.,.burton,.i.,.challenger,.b.,.Huq,.s.,.klein,.r.j.t..and.yohe,.g..2001..
chapter.18.Adaptation.to.climate.change.in.the.context.of.sustainable.development.and.equity..iPcc.third.Assessment.report,.intergovernmental.Panel.on.climate.change.
stakhiv,.e.,.and.r..Pietrowsky,.2009..Adapting.to.climate.change.in.water.resources.and.water.services..institute.for.water.resources,.u.s..Army.corps.of.engineers..Presented.at.Fifth.world.water.Forum,.istanbul,.march.2009.
stern,.sir.nicholas..2006. The Economics of Climate Change: The Stern Review..Hm.treasury..london.
113
strzepek,.k,.r..balaji,.H.,.rajaram.and.j..strzepek.2008..A.water.balance.model.for.climate.impact.Analysis.of.runoff.with.emphasis.on.extreme.events,.in.preparation
sullivan.c.A..and.j..r..meigh..2005..targeting.attention.on.local.vulnerabilities.using.an.integrated.indicator.approach:.the.example.of.the.climate.vulnerability.index..water.science.and.technology,.special.issue.on.climate.change.51.(5):.69–78.
sullivan,.c.A..and.c..Huntingford..2009..water.resources,.climate.change.and.Human.vulnerability.Proceedings.of.the.modsim.conference,.cairns,.july.2009.
tehelka..2008..climate.change:.what.men.can.do?,.3.may.2008.trenberth,.k..e.,.A..dai,.r..m.rasmussen,.and.d..b..Parsons..2003..the.changing.character.of.
Precipitation..bulletin.of.the.American.meteorological.society..84:.1205–1217.un..1996..Indicators of Sustainable Development Framework and Methodology..united.nations.
division.for.sustainable.development,.new.york.usAce.(us.Army.corps.of.engineers)..1992..guidelines.for.risk.and.uncertainty.Analysis.
in.water.resources.Planning,.vol.1.–.Principles..iwr.report.92-r-1..institute.for.water.resources..Fort.belvoir,.usA.
usePA..2008..national.water.Program.strategy:.response.to.climate.change..washington,.dc:.usePA.
vörösmarty,.c.j.,.P..green,.j..salisbury,.and.r.b..lammers..2000..global.water.resources;.vulnerability.from.climate.change.and.Population.growth.”.Science.289:.284–288.
wcrP,.2006..workshop.“understanding.sea.level-rise.and.variability”,.june.2006,.unesco.Paris:.wcrp.ipsl.jussieu.fr/workshops/sealevel.summary.statement.:.wcrp.ipsl.jussieu.fr/workshops/sealevel/reports/summary_statement_2006_1004.pdf.
willows,.r.i..and.r.k..connell.(eds.)..2003..climate.Adaptation:.risk,.uncertainty.and.decision-making..ukciP.technical.report..ukciP,.oxford.
wolf,.A..t.,.stahl,.k.,.&.macomber,.m..F..2003..conflict.and.cooperation.within.international.river.basins:.the.importance.of.institutional.capacity..water.resources.update,.125..universities.council.on.water.resources.
world.bank..2003..water.resources.sector.strategy.–.strategic.directions.for.world.bank.engagement..report.number:.28114..washington.dc:.the.world.bank.
world.bank,.2004:.The Republic of Kenya. Towards a Water Secure Kenya. Water Resources Sector Memorandum..report.no..28398.–.ke..washington.dc:.the.world.bank.
world.bank..2006..Ethiopia: Managing Water Resources to Maximize Sustainable Growth..country.water.resources.Assistance.strategy.
world.bank..2007..idA.and.climate.change:.making.climate.Action.work.for.development..report.number:.41280..washington.dc:.the.world.bank.
world.bank..2008a..development.and.climate.change:.A.strategic.Framework.for.the.world.bank.group:.technical.report..report.number:.47893..washington.dc:.the.world.bank.
world.bank,.2008b..Ethiopia: A country Study on Economic Impacts of Climate Change..report.no..46946-et..washington.dc:.the.world.bank.
world.bank,.2009a..Assessment.of.climate.impact.on.Peru’s.hydrology..development.of.a.methodology..Progress.report.no..1.
world.bank..2009b..water.and.climate.change:.impacts.on.groundwater.resources.and.adaptation.options..water.Anchor..energy,.transport.and.water.department..washington.dc:.the.world.bank.
wwF.(world.wildlife.Fund)..2009..Flowing Forward: Informing Freshwater Biodiversity and Sustainable Management in a Shifting Climate.(draft.report.prepared.for.the.world.bank).
114
115
annex a: summary of waTer PorTfolio by region
africa region
Overall water investment
Africa.has.committed.a.total.of.$2.billion.in.water.investments.in.Fy06–08,.which.account.for.12%.of.the.bank’s.lending.in.the.region.(Figure.A1)..Among.the.regions,.Africa.has.the.highest.level.of.water.investments,.both.in.terms.of.volume.(23%).and.number.of.projects.(27%)..the.2003.water.resources.sector.strategy.report.projected.growth.in.the.water.sector.to.this.region,.which.has.been.confirmed.by.the.increase.in.lending.in.the.Fy06–08.period.with.a.yearly.average.of.$685.million,.the.highest.among.all.the.regions.for.a.total.of.52.projects.for.the.entire.period.
Water investment by country
the.water.investments.are.distributed.among.27.countries.in.the.region.including.regional.projects..countries.with.the.most.number.of.projects.are.ethiopia.(seven),.kenya.(six).and.tanzania.(four).representing.a.third.of.all.water.projects.in.AFr..in.terms.of.volume,.the.largest.investments.went.to.specific.regional.projects,.and.countries.such.as.ethiopia,.kenya.and.nigeria..there.are.many.small.water.resources.investment.projects.in.the.region,.however.three.of.them.are.worth.mentioning.for.their.large.investment.amounts:.Regional and Domestic Power Markets Development Project-Inga Rehabilitation ($271.million),.Niger Basin Water Resources Development and Sustainable Ecosystems Management ($162.million).and.the.Private Power Generation (Bujagali).project ($115.million)—all.in.the.category.of.multi-purpose.systems.
Figure A1 Africa region water investment for the FY06–08 period
Lending US$M00–55–2525–125>125
$1,128 M(55%) $926 M
(45%)Services
Resources
Lending (%)
Source: world.bank,.2009.
116
Future water investments
AFR expects a major increase in number of water projects in the next two fiscal years27, from an average of 17 projects per year (FY06–08) to an average of 27 projects per year (FY09–10)—the highest among the regions..in.terms.of.lending.volume,.the.pipeline.is.weaker.than.the.current.portfolio..Africa’s.pipeline.represents.11%.of.the.total.water.lending.among.the.regions.in.Fy09–10,.a.significant.decrease.compared.to.the.active.period.with.23%.of.the.total.water.investment..moreover,.water.services.systems.are.expected.to.dominate.with.71%.of.the.projected.lending.and.61%.of.the.total.number.of.projects.
looking.at.the.pipeline.distribution.by.system,.the.largest.share.of.the.projected.lending.is.directed.towards.urban.water.and.sanitation.(53%).followed.by.irrigation.and.drainage.(16%),.water.resources.management.(14%).and.multi-purpose.facilities.(10%)..A.similar.trend.is.seen.in.terms.of.number.of.projects,.with.urban.water.and.sanitation.systems.dominating.the.water.pipeline..in.comparison.to.the.active.period,.most.increase.is.expected.in.water.resources.management.for.Fy09–10.
east asia and Pacific region
Overall water investment
the.total.active.water.investments.approved.in.Fy06–08.is.$1.7.billion.representing.12%.of.the.total.bank’s.lending.in.the.region.(Figure.A2)..water.investment.in.eAP.accounts.for.19%.of.the.
27 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure A2 East Asia and Pacific region water investment for the FY06–08 period
00–55–2525–125>125
$1,327 M(78%)
$364 M(22%)
Services
Resources
Lending US$M
Lending (%)
Source: world.bank,.2009.
117
overall.bank’s.investment.in.water,.which.is.the.third.highest.share.compared.to.other.regions..in.spite.of.the.significant.investment,.water.lending.in.the.region.has.decreased.significantly.through.the.active.period.with.a.yearly.average.lending.of.$564.million.for.a.total.of.26.projects.for.the.entire.period.
Water investment by country
there.are.seven.countries.with.water.investments.in.the.region.for.the.Fy06–08.period..Following.the.same.pattern.identified.in.the.2003.water.resources.sector.strategy,.china.continues.to.dominate.regional.water.lending.with.almost.70%.of.the.overall.water.investments.in.the.region.(58%.in.terms.of.number.of.projects)..most.of.these.investments.are.concentrated.in.urban.water.and.sanitation.(60%).consisting.of.projects.of.significant.investment:.Henan Towns Water Supply and Sanitation project ($143.million),.Second Liaoning Medium Cities Infrastructure project ($142.million).and.Shanghai Urban Environment APL Phase 2.($126.million)..china.also.has.a.share.of.investment.going.into.irrigation.and.drainage.(14%).corresponding.to.a.lending.of.$136.million.(Irrigated Agriculture Intensification Loan III),.and.many.small.projects.with.water.resources.systems..vietnam.accounts.for.the.second.largest.share.of.water.investments.(16%),.followed.by.indonesia.(11%).and.Philippines.(4%)..except.for.china,.there.is.little.investment.into.water.resources.systems.by.other.country.in.the.region.
Future water investment
water.investments.in.Fy09.and.Fy10.are.expected.to.increase.considerably.compared.to.the.Fy06–08.period..the.eAP.region.is.expected.to.account.for.24%.of.all.the.water.investments.(19%.in.terms.of.project.number)..water.services.systems.will.continue.to.dominate,.however.at.a.lesser.degree.(67%.in.terms.of.investments.and.57%.in.terms.of.number.of.projects).
Projections.at.the.water.system.level.show.that.53%.of.the.lending.is.in.urban.water.and.sanitation.followed.by.19%.in.multi-purpose.systems..eAP.is.expected.to.have.the.largest.share.(36%).of.watershed.management.investment.among.all.regions..in.terms.of.number.of.projects,.urban.water.and.sanitation.system.is.also.expected.to.dominate.the.pipeline..most.increase.for.the.Fy09–10.period.is.expected.in.water.resources.systems28,.more.specifically.in.multipurpose.facilities.
europe and Central asia region
Overall water investment
the.total.active.water.investments.approved.in.Fy06–08.is.$1.3.million,.which.represents.10%.of.the.total.bank’s.lending.in.the.region.(Figure.A3)..Among.the.regions,.europe.and.central.Asia.(ecA).region.accounts.for.14%.of.the.total.water.investments.and.15%.of.total.number.of.projects..in.the.2003.sector.strategy.portfolio.review,.ecA.was.identified.as.the.region.with.the.smallest.share.of.water.investments.in.the.bank..this.is.no.longer.the.case.as.the.region.is.increasing.its.lending,.and.has.shown.an.average.lending.of.$421.million.with.a.total.of.29.projects.for.the.entire.Fy06–08.period.
28 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
118
Water investment by country
water.investment.is.distributed.between.16.countries.in.the.region.with.the.bulk.of.water.investment.concentrated.in.Azerbaijan.(39%)..investment.in.the.country.is.all.going.into.urban.water.supply.and.sanitation.with.two.significant.projects,.National Water Supply & Sanitation.($225.million).and.Second National Water Supply and Sanitation project.($257.million)..the.second.and.third.largest.share.of.investments.is.in.Poland.(13%).with.a.project.in.flood.control.and.water.resources.management,.and.croatia.(10%).with.a.project.mainly.in.urban.water.and.sanitation.with.components.in.flood.control.and.water.resources.management..the.remaining.lending.is.distributed.among.13.countries..in.terms.of.number.of.projects,.Azerbaijan.has.four.projects.followed.by.Armenia.and.kyrgyz.(with.three.projects.each).
Future water investment
water.investments.in.the.ecA.region.have.increased.substantially.over.the.last.couple.of.years.and.this.trend.is.anticipated.to.continue.over.the.Fy09–10.period..the.pipeline.for.ecA.represents.12%.of.the.total.bank’s.water.investment..water.services.systems.is.expected.to.continue.to.dominate,.both.in.terms.of.investments.(73%).and.number.of.projects.(67%),.with.an.average.lending.of.over.$300.million.per.year..At.the.system.level,.significant.increase.in.investment.is.expected.for.rural.water.and.sanitation,.irrigation.and.drainage.and.multi-purpose.facilities..urban.water.and.sanitation.will.continue.to.be.the.main.driver.of.water.investments,.however,.irrigation.and.drainage.and.multi-purpose.facilities.are.expected.to.account.for.a.considerable.share.of.total.investments..investments.in.flood.control.represent.a.smaller.share.(10%).in.the.pipeline;.however,.when.compared.to.other.regions,.ecA.still.represents.a.substantial.share.(20%).of.flood.control.investments.in.the.bank29.
29 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure A3 Europe and Central Asia region water investment for the FY06–08 period
Lending US$M00–55–2525–125>125
Services
Resources
Lending (%) $949 M(75%)
$314 M(25%)
Source: world.bank,.2009.
119
latin america and Caribbean region
Overall water investment
the.total.active.water.investments.approved.in.latin.America.and.caribbean.region.(lcr).in.the.Fy06–08.period.is.$1.2.billion.which.represents.8%.of.the.total.bank’s.lending.in.lcr,.the.lowest.compared.to.other.regions.(Figure.A4)..the.lcr’s.portfolio.corresponds.to.13%.of.the.overall.bank.investments.in.water..yearly.average.lending.for.lcr.in.Fy06-Fy08.is.$390.million.for.a.total.of.40.projects.for.the.entire.period.
Water investment by country
For.the.Fy06–08.period,.there.are.40.projects.in.16.countries.with.most.of.the.lending.going.to.Argentina.(23%),.mexico.(23%).and.brazil.(17%)..the.large.amount.of.lending.in.Argentina.and.mexico.represent.only.three.projects.in.each.country:.Argentina.focuses.on.urban.water.and.sanitation.with.a.small.portion.towards.watershed.management,.while.mexico.has.a.balanced.investment.between.urban.water.and.sanitation.and.water.resources.management..there.is.one.project.in.each.country.worth.mentioning.due.to.their.large.investment:.Infrastructure Project for the Province of Buenos Aires APL2 ($146.million).in.Argentina.and.Climate Change DPL ($250.million).in.mexico..Although.there.is.significant.water.investment.in.brazil.(a.total.of.$200.million),.the.lending.is.well.distributed.between.ten.projects.with.most.investment.going.into.water.resources.management.and.urban.water.and.sanitation.
Future water investment
total.water.investment.for.the.Fy09–10.is.expected.to.double.in.comparison.to.the.Fy06–08.period.accounting.for.24%.of.the.overall.bank’s.pipeline.for.water..this.increase.is.the.highest.of.
Figure A4 Latin America and Caribbean region water investment for the FY06–08 period
Lending US$M00–55–2525–125>125
$931 M(80%)
$239 M(20%)
Services
Resources
Lending (%)
Source: world.bank,.2009.
120
any.region.with.most.lending.directed.towards.water.services.(74%),.although.lending.for.water.resources.is.also.expected.to.increase.by.almost.threefold.
Projection.at.the.water.system.level.is.not.expected.to.vary.significantly.from.the.current.portfolio..About.64%.of.lending.and.42%.of.projects.is.expected.to.be.in.urban.water.and.sanitation.followed.by.25%.of.lending.and.29%.of.projects.into.water.resources.management..significant.increase.in.investment.is.expected.not.only.for.water.resources.management,.but.also.for.rural.water.and.sanitation..increase.in.lending.is.also.expected.in.urban.water.and.sanitation.and.irrigation.and.drainage,.though.to.a.lesser.degree30.
middle east and north africa region
Overall water investment
the.middle.east.and.north.Africa.(mnA).region.has.committed.a.total.of.$650.million.in.water.investments.for.Fy06–08,.which.accounts.for.14%.of.the.overall.regional.investments.(Figure.A5)..Although.a.significant.portion.of.investment.is.going.to.water,.compared.to.other.regions,.this.represents.a.small.portion.(7%).of.the.bank’s.total.commitment.in.water..despite.the.relative.low.water.investment,.lending.increased.during.the.last.three.fiscal.years.with.a.yearly.average.investment.of.$217.million.corresponding.to.a.total.of.16.projects.for.the.entire.period.
Water investment by country
water.investments.are.distributed.among.eight.countries.in.the.region..of.the.16.projects.approved.in.the.Fy06-Fy08.period.(with.ten.projects.corresponding.to.2008.alone),.egypt.has.the.largest.
30 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure A5 Middle East and North Africa region water investment for the FY06–08 period
Lending US$M00–55–2525–125>125
$576 M(89%)
$74 M(11%)
Services
Resources
Lending (%)
Source: world.bank,.2009.
121
share.of.commitments.(40%),.followed.by.iraq.(26%),.tunisia.(16%),.morocco.(9%),.and.yemen.(6%)..there.are.three.significant.projects.in.the.region,.two.in.egypt.(West Delta Water Conservation and Irrigation Rehabilitation project of.$141.million.and.the.Integrated Sanitation & Sewerage Infrastructure project.of.$120.million).and.one.in.iraq.(Emergency Water Supply Project.of.$104.million).corresponding.to.56%.of.the.total.water.regional.investment..of.the.six.projects.with.water.resources.systems,.the.one.with.the.largest.commitment.is.in.iraq—Dokan and Derbandikhan Emergency Hydro Power Project ($40.million).
Future water investment
For.the.Fy09–10.period31,.the.region.is.expected.to.increase.its.yearly.average.lending.investment.in.the.sector..Among.the.regions,.mnA.would.represent.5%.of.the.overall.water.commitments.in.the.bank,.slightly.lower.than.the.Fy06–08.period..most.of.the.lending.is.again.expected.for.projects.with.water.services.(86%).and.will.continue.being.the.highest.share.of.any.region.
Projection.at.the.water.system.level.show.most.of.the.lending.going.to.urban.water.and.sanitation,.irrigation.and.drainage,.and.water.resources.management,.each.representing.a.significant.portion.of.the.total.water.pipeline.in.the.region.(44%,.37%.and.14%.respectively)..there.is.a.percentage.increase.in.lending.expected.for.water.resources.management.and.irrigation,.while.there.is.a.percentage.decrease.expected.for.rural.water.and.sanitation,.showing.a.significant.decline.from.the.Fy06–08.period.
south asia region
Overall water investment
south.Asia.region.(sAr).has.committed.a.total.of.$1,945.million.in.water.investment.for.Fy06–08,.accounting.for.14%.of.the.overall.regional.investment.(Figure.A6)..Among.the.regions,.sAr.represents.22%.of.the.overall.water.investment.(15%.in.terms.of.number.of.projects),.which.is.the.second.largest.share.after.AFr..water.investment.in.the.region.has.steadily.increased.during.this.period,.with.yearly.average.of.$648.million.corresponding.to.a.total.of.28.projects.for.the.entire.period.
Water investment by country
water.investment.in.sAr.for.Fy06–08.is.distributed.among.six.countries.in.the.region..india.is.the.driver.in.the.region.representing.68%.of.water.investments.(less.so.in.terms.of.number.of.projects.–36%)..Pakistan.has.a.considerable.share.of.investments.(10%),.followed.by.bangladesh,.nepal,.Afghanistan.(6%.each),.and.sri.lanka.(4%)..the.projects.with.the.largest.investments.for.this.period.are.in.india:.Rampur Hydropower Project.($400.million).and.Tamil Nadu Irrigated Agriculture Modernization and Water-Bodies Restoration and Management Project.($291million)..Pakistan.has.also.a.large.irrigation.project:.Sindh Water Sector Improvement Project Phase I ($120.million).
31 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
122
Future water investment
in.the.coming.two.fiscal.years.(Fy09-Fy10),.the.projection.for.water.lending.in.the.sAr.region.is.expected.to.increase.to.an.average.lending.of.over.$1.billion.compared.to.$648.million.per.year.for.the.Fy06–08.period..sAr.is.expected.to.represent.26%.of.the.bank’s.lending.in.water..Projects.with.water.services.systems.are.anticipated.to.dominate.62%.of.the.investments,.with.a.stronger.focus.on.urban.water.and.sanitation.(37%).and.irrigation.and.drainage.(26%)..likewise,.lending.for.multi-purpose.facilities.(25%).is.expected.to.continue.strong.and.to.be.the.highest.of.any.region..there.is.also.a.large.lending.increase.expected.for.flood.control.and.watershed.management.systems..unlike.the.Fy06–08.period,.sAr.is.expected.to.decrease.its.investment.in.rural.water.and.sanitation.systems,.thus.the.region.is.no.longer.expected.to.be.the.largest.contributor.of.investments.towards.that.system.32
32 Pipelineresultsshouldbereadwithcautionbecauseofthechangesinapprovaldates,commitmentamounts,etc,duringthepreparationphaseoftheproject.
Figure A6 South Asia region water investment for the FY06–08 period
Lending US$M00–55–2525–125>125
$1,241 M(64%) $703 M
(36%)Services
Resources
Lending (%)
Source: world.bank,.2009.
123
annex b: risk-based deCision making frameworks
united kingdom Climate impacts Programme
in.may.2003,.ukciP.published.a.technical.report.titled.Climate Adaptation: Risk, Uncertainty and Decision-making.(willows.and.connell,.2003)..this.report.“recommends.a.structured.framework.and.associated.guidance.to.promote.good.decision-making”.(willows.and.connell,.2003,.p..v)..the.framework.consists.of.the.eight.stages.listed.here.and.illustrated.in.Figure.b1.
•.stage.1:.identify.problem.and.objectives
•.stage.2:.establish.decision-making.criteria
•.stage.3:.Assess.risk
•.stage.4:.identify.options
•.stage.5:.Appraise.options
•.stage.6:.make.decision
•.stage.7:.implement.decision
•.stage.8:.monitor,.evaluate,.and.review.
According.to.ukciP:.“the.aim.of.using.the.framework.is.for.the.decision-maker.to.identify.where.climate.change.is.a.material.consideration..where.climate.or.climate.change.are.significant,.the.decision-maker.should.aim.to.identify.adaptation.options.for.the.decision.(such.as.no.regret.options).that.are.robust.to.the.key.sources.of.uncertainty”.(willows.and.connell,.2003,.p..6).
Pros
this.framework.focuses.on.the.entire.decision-making.context..issues.of.problem.definition.are.addressed.in.stage.1.and.rechecked.in.stage.6..“Formulating.the.issue.represents.a.critical.stage.for.the.decision-maker..before.embarking.on.a.decision-making.process,.it.is.essential.to.understand.the.reasons.for.the.decision.being.made,.the.decision-maker’s.broad.objectives,.and.the.wider.context.for.the.decision”.(willows.and.connell,.2003,.p..10).
this.framework.quickly.addresses.substantive.issues.by.operationalizing.the.stage.1.problem.definition.in.stage.2..“this.stage.sets.out.the.establishment.of.criteria.for.decision-making..the.broad.objectives.of.the.decision-maker,.set.out.under.stage.1,.need.to.be.translated.into.operational.criteria.that.can.be.used.in.a.formal.risk.assessment,.and.against.which.the.performance.of.different.options.and.the.subsequent.decision.can.be.appraised”.(willows.and.connell,.2003,.p..14)..Although.not.every.adaptation.policy.is.amenable.to.such.formal.analysis,.using.formal.criteria,.when.possible,.maximizes.accountability,.enables.unambiguous.evaluation.of.policy.success.or.failure,.and.assists.in.identifying.informational.needs.
ukciP.attempted.to.make.its.framework.context.sensitive.at.key.points.such.as.the.stage.3.risk.assessment.and.the.stage.5.option.appraisal.by.indicating.that.under.certain.circumstances,.resource-.and.time-intensive.steps.can.be.skipped.entirely..the.conditional.nature.of.these.steps,.however,.faces.severe.practical.limitations,.as.discussed.below.under.“cons.”
ukciP.included.stage.7.implementation.and.stage.8.monitoring.as.part.of.their.framework..However,.these.elements.of.the.decision-making.process.are.not.discussed.because:.“the.prime.
124
purpose.of.these.guidelines.is.to.help.the decision-maker.reach.a.decision.and.we.do.not therefore.discuss.in.detail.the.“best”.means.to.implement.and.monitor.a.decision” (willows.and.connell,.2003,.p..39).
Cons
the.stage.3.risk.assessment.in.this.framework.is.a.detailed.analysis.that,.in.our.judgment,.requires.expert.practitioners.to.implement..despite.the.attempt.to.simplify.this.step.by.subdividing.it.into.three.“tiers”:.“risk.screening,”.“generic.quantitative.risk.assessment,”.and.“detailed.quantitative.risk.assessment,”.its.complexity.may.be.a.barrier.to.its.use.by.decision-makers..namely,.by.subdividing.and.contextualizing.this.step.in.the.framework,.decision-makers.may.either.ignore.this.step.or.delegate.it.to.technical.experts..it.is.not.clear.that.technical.experts.are.either.needed.for.many.decisions.or.the.appropriate.authority.for.deciding.when.sufficient.knowledge.has.been.accumulated.given.time.and.resource.constraints..the.stage.5.option.appraisal.also.has.three.tiers.and.may.suffer.from.similar.problems.
stage.4,.“identify.options,”.follows.the.stage.3.risk.assessment..in.reality,.many.adaptations.exist.that.are.no.regret.policies.which.offer.benefits.under.current.climate.as.well.as.under.projected.changes.in.climate..such.policies.do.not.require.the.preceding.stage.3.risk.assessment.for.their.justification..in.many.circumstances,.engaging.in.stage.4.before.stage.3.can.reduce.the.time.and.resource.demands.of.decision-making.by.identifying.policy.options.that.do.not.require.a.risk.assessment..indeed,.it.is.our.contention.that.options.should.be.identified.early.in.the.decision-making.process.
Figure B1 The UKCIP framework
Receptors, exposure units &risk assessment endpoints
NO
YES
YES
6 Make decision
Problemdefined
correctly?Criteriamet?
NO
1 Identify problem & objectives
2 Establish decision-making criteria
3 Assess risk
4 Identify options5 Appraise options
7 Implement decision
8 Monitor
Source: willows.and.connell,.2003,.p..7,.Fig..1.
125
Although.this.framework.claims.to.be.“circular”.and.“iterative”.by.incorporating.“feedback”.mechanisms.and.promoting.“adaptive.management,”.many.people,.including.decision-makers,.may.have.difficulty.understanding.how.different.stages.of.a.process.like.this.feedback.on.one.another..According.to.Figure.b1,.almost.every.stage.in.this.framework.should.feed.back.to.earlier.stages..only.stage.6,.“make.decision,”.has.formal.logical.criteria.for.deciding.whether.to.revisit.previous.stages..in.essence,.the.interrelationships.between.framework.stages.may.be.too.complex.to.be.useful.to.many.decision-makers.who.are.limited.by.incomplete.information.and.multiple.demands.on.their.time.
australian greenhouse office
in.2006,.the.Australian.greenhouse.office.published.a.report.titled.Climate Change Impacts & Risk Management: A Guide for Business and Government.(broadleaf.and.mjA,.2006)..According.to.the.report,.“the.guide.provides.a.framework.for.managing.the.increased.risk.to.organizations.due.to.climate.change.impacts..the.prime.focus.of.the.guide.is.on.the.initial.assessment.and.prioritization.of.these.risks”.(broadleaf.and.mjA,.2006,.p..9)..notably,.this.framework.uses.the.Australian.and.new.Zealand.standard.for.risk.management,.As/nZs.4360.(standards.Australia,.2004),.to.extend.the.application.of.this.widely.used.guidance.on.risk.management.in.the.public.and.private.sectors.to.risks.generated.by.climate.change.and.its.impacts..the.framework.consists.of.the.five.steps.and.two.umbrella.activities.listed.here.and.illustrated.in.Figure.b2.
•.step.1.establish.the.context•.step.2.identify.the.risks•.step.3.Analyze.the.risks•.step.4.evaluate.the.risks•.step.5.treat.the.risks•.umbrella.activities
•.communication.and.consultation•.monitor.and.review
Figure B2 The Australian framework
Objectives
Stakeholders
Criteria
Key elements
Climate scenarios
Likelihoods
Consequences
Level of risk
Rank risks
Screen minor risks
Select the best
Develop plans
Implement
COMMUNICATE AND CONSULT
MONITOR AND REVIEW
ESTABLISHTHE CONTEXT
What canhappen
How could ithappen
IDENTIFYTHE RISKS
Review controls
ANALYSETHE RISKS
Evaluate risks
EVALUATETHE RISKS
Identify options
TREATTHE RISKS
source:.broadleaf.and.mjA,.2006,.p..19,.Fig..5.
126
Pros
the.Australian.framework.offers.a.simple,.linear.decision.process.that.can.be.implemented.by.a.wide.range.of.people.without.requiring.specific.expertise.in.risk.assessment.methodologies..this.is.particularly.important.in.creating.a.framework.that.can.be.used.by.decision-makers..According.to.the.Australian.greenhouse.office,.“the.process.requires.only.standard.climate.scenarios,.a.general.understanding.of.the.impacts.of.climate.change,.comprehensive.understanding.of.the.business.or.organization.and.sound.professional.judgment”.(broadleaf.and.mjA,.2006,.p..18).
even.though.the.decision.process.as.outlined.is.linear,.it.also.allows.for.interconnectedness.through.the.two.umbrella.functions.of.communication/consultation.and.monitor/review..According.to.the.greenhouse.office,.“communication.and.consultation.are.key.components.of.any.risk.management.process.and.are.required.at.each.step..success.relies.on.achieving.a.high.level.of.creative.input.and.involving.all.parties.with.a.role.to.play.in.identifying,.assessing.and.managing.climate.change.risks..in.both.the.planning.and.execution.of.the.risk.management.process.it.is.important.to.ensure.that.all.those.who.need.to.be.involved.are.kept.informed.of.developments.in.the.understanding.of.risks.and.the.measures.taken.to.deal.with.them”.(broadleaf.and.mjA,.2006,.p..20)..Also,.regarding.the.monitor/review.umbrella.function,.“the.outputs.of.all.steps.of.the.risk.management.process.must.be.kept.under.review.so.that,.as.circumstances.change.and.new.information.comes.to.hand,.plans.can.be.maintained.and.kept.up.to.date”.(broadleaf.and.mjA,.2006,.p..20).
the.Australian.framework.also.allows.for.multiple.levels.of.analysis.as.circumstances.dictate..“to.allow.effort.to.be.directed.towards.the.highest.priority.issues,.a.two-stage.approach.to.risk.assessment.is.recommended.to.users.of.this.guide:.(1).An.initial.assessment.identifies.and.sifts.risks.quickly,.followed.by.treatment,.planning,.and.implementation.for.those.risks.that.clearly.require.it;.and.(2).detailed.analysis.is.used.where.additional.information.is.needed.to.determine.whether.treatment.is.required.or.what.form.of.treatment.to.adopt”.(broadleaf.and.mjA,.2006,.p..21)..this.allows.for.the.differential.treatment.of.policy.actions.that.are.no.regret.and.those.that.may.have.significant.costs.or.externalities.that.merit.greater.analysis.and.consideration.
Cons
the.front.end.of.this.framework.includes.many.critical.tasks.within.step.1,.“establish.the.context,”.such.as.“clarifying.explicitly.the.objectives.of.the.organization,”.“establishing.success.criteria.against.which.risks.to.the.organization’s.objectives.can.be.evaluated,”.and.“identifying.stakeholders.and.their.objectives.and.concerns”.(broadleaf.and.mjA,.2006,.p..19)..However,.because.so.many.important.tasks.are.aggregated.into.a.single.step.in.the.framework,.some.of.those.tasks.could.be.neglected.or.presumed,.and.decision-makers.might.proceed.to.the.technical.aspects.of.risk.assessment.without.critically.considering.these.front-end.tasks.
the.Australian.framework.does.not.contain.any.information.or.guidance.about.turning.a.decision.into.action..essentially,.this.framework.neglects.the.important.tasks.of.policy.construction,.promotion,.and.implementation—failing.not.only.to.discuss.them,.but.even.to.mention.them.as.part.of.the.decision.process.
this.framework.proposes.to.execute.a.decision.process.and.risk.assessment.through.a.single.methodology—the.workshop.format..this.includes.steps.2,.3,.and.4,.the.identification,.analysis,.and.evaluation.of.risks..Although.qualitatively.assessing.risks.can.be.very.useful.for.involving.
127
stakeholders.and.for.avoiding.the.tendency.to.get.bogged.down.in.technical.analyses.that.may.not.be.necessary.to.take.action,.there.are.times.when.a.more.formal.risk.assessment.is.appropriate..this.is.particularly.the.case.when.the.decision-maker.is.a.technical.expert,.when.costs.may.be.very.high,.when.the.range.of.risks.due.to.climate.change.is.very.wide,.when.significant.uncertainties.prevent.an.accurate.assessment.of.risk.likelihood.or.consequence,.and.so.on..Although.the.detailed.risk.assessment.is.meant.to.address.these.issues,.the.Australian.greenhouse.office.still.claims,.“the.process.of.implementing.the.detailed.analysis.will,.in.most.cases,.be.particular.to.your.organization.and.to.the.different.risks.faced.by.your.organization..For.this.reason,.it.is.not.feasible.or.appropriate.to.offer.specific.guidance.on.the.detailed.analysis”.(broadleaf.and.mjA,.2006,.p..54).
128
129
annex C: adaPTaTion oPTions for mulTi-PurPose infrasTruCTure
dam structure
concrete.dams.have.greater.adaptive.capacity.than.embankment.dams,.owing.to.the.fact.that.they.are.normally.founded.on.rock,.and.can.be.strengthened.to.withstand.higher.flood.loadings—including.overtopping.in.some.circumstances..embankment.dams.cannot.be.modified.readily.to.the.same.extent,.and.are.therefore.more.challenging.to.adapt.
since.foundation.conditions.often.dictate.the.type.of.dam.that.can.be.economical.for.a.given.project.site,.criteria.that.involve.climate.change.impacts.will.likely.not.drive.the.decision..nonetheless,.climate.factors.should.be.considered.in.evaluating.the.type.and.size.of.dam.to.be.constructed..siting.studies.may.consider.configuring.the.dam.in.such.a.way.as.to.enable.economical.future.raising,.perhaps.through.the.use.of.saddle.dams.along.reservoir.rims..Another.strategy.would.be.to.consider.use.of.multiple.sites.to.achieve.the.head.or.storage.objectives.of.a.single-dam.development..in.such.cases,.it.may.be.that.two.smaller.developments.can.have.a.smaller.environmental.footprint.than.one.large.dam,.thereby.providing.added.value.to.this.solution.
reservoir storage
reservoir.storage.and.yield.is.a.function.of.the.storage.volume.required.to.produce.the.desired.yield.against.a.certain.probability.of.exceedance.(or.failure)..it.is.one.of.the.early.planning.activities.because.much.of.the.built.infrastructure.and.the.configuration.of.dam.components.depend.upon.this.parameter.
once.a.given.site.for.the.reservoir.is.selected.(based.on.a.host.of.geologic,.hydrologic,.and.topographic.criteria).then.the.ability.to.provide.the.desired.yield.is.a.function.of.the.minimum.and.maximum.reservoir.levels.necessary.to.provide.the.active.storage..the.minimum.level.is.determined.based.upon.sedimentation.criteria,.while.the.top.of.dam.elevation.is.set.by.the.optimization.of.flood.routing.studies.and.dam.stability.in.order.to.establish.the.optimum.trade-off.between.flood.storage.and.peak.reduction.versus.spillway.head.and.discharge.capacity.
so.this.component.governs.the.dam.height.and.spillway.capacity,.which.are.often.the.two.most.expensive.components.of.the.project..this.also.has.socioeconomic.implications.relating.to.resettlement.of.marginal.populations.
use.of.the.term.“optimum”.immediately.raises.a.flag,.because.it.implies.that.a.host.of.competing.criteria.has.been.used.to.determine.a.trade-off.that.is.invariant..this.is.counter.to.the.entire.concept.of.potential.unknown.climate.change.impacts.that.must.be.designed.against..For.future.projects.in.the.planning.and.design.stage,.it.is.now.prudent.to.consider.more.variability.and.another.degree.of.freedom.than.has.traditionally.been.the.case.
use.of.top.down.probabilistic.analysis.may.require.information.and.data.that.is.not.available.(or.highly.uncertain)..An.interesting.alternative.hereto.is.the.use.of.risk—based.decision.models,.which.generate.a.large.number.of.scenarios.based.on.monte-carlo.simulations.and.then.analyze.the.outcomes.for.a.range.of.scenarios.
For.existing.project.vulnerabilities,.adaptation.will.involve.means.of.enlarging.the.reservoir.storage.volume,.either.by.raising.the.maximum.operating.level,.or.lowering.the.minimum.level,.or.both..
130
lowering.the.minimum.level.is.problematic,.since.it.is.a.function.of.sedimentation.and.would.require.expensive.underwater.construction..raising.the.maximum.level.could.require.modifications.to.upgrade.dam.stability.or.increase.spillway.capacity,.or.both..these.modifications.can.also.be.very.expensive..Another.option.for.projects.which.are.part.of.a.multi-project.basin.development.is.to.distribute.the.storage.among.multiple.locations,.either.at.existing.reservoirs.or.at.new.sites,.where.additional.storage.can.economically.be.provided.
service & auxiliary spillways
depending.upon.the.project.configuration,.the.service.and.auxiliary.spillway.system.can.be.the.second-most.expensive.component.of.the.project,.after.the.dam..An.exception.would.be.a.low-head.run-of-river.project.where.the.dam.itself.serves.as.an.overflow.spillway.
For.large.storage.reservoirs,.a.reservoir.routing.analysis.is.done.to.analyze.and.optimize.the.trade-off.between.flood.inflow,.reservoir.storage,.and.project.outflow.so.that.the.spillway.system.is.properly.designed..service.spillways.are.generally.massive.concrete.structures,.founded.on.sound.rock.or.constructed.integrally.with.a.concrete.dam..Auxiliary.spillways.normally.traverse.one.of.the.dam.abutments,.and.can.consist.of.an.overflow.weir.and.channel,.or.may.have.an.erodible.“fuse-plug”.control.to.prevent.premature.operation.of.the.auxiliary.spillway.
the.primary.criterion.for.designing.spillways.for.climate.change.is.the.selection.of.the.flood.peak.discharge.and.volume.that.will.govern.the.design..in.most.cases,.this.is.the.Probable.maximum.Flood.(PmF),.which.is.derived.from.the.Probable.maximum.Precipitation.(PmP),.along.with.watershed.characteristics..since,.in.the.climate.changed.future,.both.the.precipitation.and.the.watershed.characteristics.(due.to.temperature,.vegetation,.and.soil.moisture.and.groundwater.conditions).can.vary,.solutions.must.consider.variations.in.both.rainfall.and.runoff.characteristics.
even.in.the.absence.of.a.“return.period”.concept.in.the.case.of.the.PmF,.the.uncertainty.of.how.PmP.and.watershed.characteristics.may.change.in.future.presents.a.challenge.to.the.designer..in.the.developed.world,.hydrometeorology.advances.have.been.incorporated.into.PmP.and.PmF.studies.to.enable.site-specific.assessments.that.provide.a.more.rational.basis.for.project.planning.and.design..the.cost.of.such.investigations.is.often.economical.when.compared.to.the.cost.of.providing.additional.spillway.capacity.
retrofitting.existing.spillways.to.provide.additional.capacity.has.been.a.routine.activity.in.the.developed.world,.where.advances.in.hydrologic.analysis,.dam.failures,.and.large.populations.at.risk.have.led.to.regulatory.requirements.to.provide.increased.flood.protection.at.“high-hazard”.dams..these.measures.can.include:
•.Providing.gates.atop.existing.ungated.spillways;•.raising.gate.heights,.or.adding.additional.gated.bays;•.stability.improvements.to.allow.overtopping.of.critical.structures.without.failure;•.Provision.of.additional.auxiliary.spillway.capacity;.or•.combinations.of.the.above.
A.common.thread.among.all.of.these.options.is.high.cost,.underscoring.the.benefits.of.designing.and.building.“adequate”.spillway.systems.from.the.beginning.
131
For.less.severe,.more.frequent.flood.conditions,.operational.measures.to.predict.flood.events.either.seasonally.or.in.real-time.may.be.employed..this.may.enable.pre-lowering.(“voiding”).of.the.reservoir.storage.in.order.to.better.manage.expected.flood.runoff.or.events..For.example,.the.city.of.new.york.uses.snow.survey.data.to.enable.“voiding”.of.downstream.water.supply.reservoirs.in.order.to.provide.flood.control.benefits.without.adversely.impacting.water.supply..the.volume.of.voiding.is.limited.to.one-half.of.the.predicted.snowpack,.thereby.ensuring.that.the.reservoir.will.refill.for.the.coming.supply.season.
intake and low-level outlet works
Intakes..much.of.the.above.discussion.on.options.for.increasing.reservoir.storage.is.applicable.to.the.intake.works,.as.this.is.the.means.of.exploiting.the.available.storage..raising.the.intake.works.along.with.a.raised.reservoir.is.likely.required,.since.criteria.for.maximum.allowable.entrance.velocities.(to.prevent.debris.and.fish.entrainment).govern.the.size,.location.and.number.of.intake.ports.required.
modification.of.existing.intakes.to.accommodate.lower.operating.levels.is.difficult.and.expensive.to.achieve..building.such.flexibility.into.the.planning.and.design.of.new.intakes.is.the.recommended.approach..of.equal.importance.is.to.provide.proper.watershed.management.to.minimize.soil.erosion.and.siltation.problems.in.the.reservoir..in.tropical.and.subtropical.areas,.vegetation.management—both.terrestrial.and.aquatic—is.also.necessary..Hydropower.production.in.Zambia.has.been.recently.impacted.due.to.excessive.aquatic.vegetation.clogging.hydropower.plant.intakes.
Low-Level Outlets..Adapting.low-level.outlet.works.to.climate.change.impacts.presents.many.of.the.same.challenges.as.tunnels..often.designed.to.a.fixed.capacity.and.size,.and.imbedded.within.project.structures.below.normal.operating.levels,.such.outlets.are.not.easily.or.economically.adapted..Possible.strategies.may.include:
•.design.outlet.works.with.redundant.water.passages.that.can.be.closed.off.or.opened.as.future.conditions.warrant;.or
•.Provide.parallel.component.systems—water.supply.outlets.and.spillway.outlets,.for.example—that.can.be.used.interchangeably.or.in.tandem.as.needs.arise.
Hydropower plant
key.design.elements.of.hydropower.plants.are.the.intakes,.water.conductors,.and.turbine-generator.sets..once.these.elements.are.sized.and.built,.they.are.not.readily.changed..in.the.past,.it.has.been.common.practice.in.the.planning.and.design.stages.to.consider.provisions.for.staged.development.of.the.power.component,.providing.block-outs.and.skeleton.bays.for.future.construction.of.additional.water.conductors.and.installation.of.turbine-generator.sets..However,.this.adds.to.the.upfront.cost.while.risking.a.stranded.investment,.if.the.need.for.the.expansion.does.not.arise.
Hydroelectric.equipment.is.designed.to.operate.within.a.given.range.of.head,.discharge.and.efficiency.conditions..there.is.some.flexibility.within.a.given.equipment.design.for.(less).efficient.operation.above.and.below.the.design.optimum..However,.the.number.of.units,.sizes.of.intakes.and.water.conductors,.and.related.structural.components.are.relatively.fixed.once.they.are.sized.and.constructed.
132
Another.key.factor.in.adapting.hydroplants.to.climate.change.is.the.dispatch.criteria.for.fitting.the.hydropower.plant.into.the.overall.system.demand.profile..Hydroplants.are.frequently.operated.as.“load-following”.or.“peaking”.plants,.because.of.their.inherent.ability.to.increase.or.decrease.generating.capacity.and.energy.output.on.a.short-term.time.horizon.
Adapting.hydropower.plants.to.a.climate-change.future.requires.comprehensive.analysis.of.power.and.energy.demand.to.be.served,.water.availability.under.a.relevant.range.of.future.climate.scenarios,.and.cost.of.power.versus.cost.of.construction.to.achieve.the.required.return.on.investment.(roi).from.the.plant..consideration.of.these.factors.will.inevitably.lead.to.providing.multiple.units.of.equal.or.varying.capacity,.so.that.a.wide.range.of.production.and.demand.scenarios.can.be.accommodated.
Tunnels
tunnels.often.serve.project.performance.needs,.taking.maximum.advantage.of.the.available.driving.head.from.the.reservoir..sizing.of.these.structures.is.usually.done.to.a.fairly.tight.specification.of.design.discharge,.and.they.have.specific.requirements.(e.g.,.requiring.plant.shutdown.to.effect.any.modifications).that.can.make.post-construction.modifications.difficult.and.expensive.
in.certain.applications,.use.of.tunnels.as.water.conductors.for.hydropower.plants,.outlet.works,.and.even.spillway.systems.is.a.sound.technical.and.economic.decision..However,.for.many.of.the.same.reasons.described.above.for.hydroplants,.they.are.not.readily.modified.or.retrofitted.post-construction.
this.again.speaks.to.the.premium.placed.upon.the.upfront.planning.and.design.activities.necessary.to.size.the.works.and,.where.possible,.climate-proof.them..one.option.for.tunnels.is.to.design.them.to.operate.as.open.channels,.but.with.the.ability.to.function.safely.and.reliably.as.pressure.conduits.at.higher.discharge.levels.
open channels
open-channel.conveyances.or.canals.provide.some.measure.of.adaptability.in.response.to.climate.change.impacts..solutions.will.generally.involve.reducing.freeboard,.or.widening.or.deepening.the.cross-section.by.excavation..it.is.more.expensive.to.modify.a.lined.channel.than.an.unlined.channel,.and.even.deepening.of.an.unlined.channel.might.require.the.introduction.of.a.lining.if.significantly.different.foundation.materials.are.encountered..depending.upon.freeboard.and.lining.conditions,.canals.can.operate.at.higher-than-design.discharges.by.modifying.the.control.structures.to.allow.it..it.may.therefore.be.that.the.adaptability.of.the.control.structures.governs.the.adaptability.of.the.canal,.rather.than.the.channel.itself.
133
annex d: glossary of Terms
(source:.bates.et.al,.2008,.except.where.noted)
adaptation
initiatives.and.measures.to.reduce.the.vulnerability.of.natural.and.human.systems.against.actual.or.expected.climate.change.effects..various.types.of.adaptation.exist,.e.g..anticipatory.and.reactive,.private.and.public,.and.autonomous.and.planned..examples.are.raising.river.or.coastal.dikes,.the.substitution.of.more.temperature-shock.resistant.plants.for.sensitive.ones,.etc.
adaptive capacity
the.whole.of.capabilities,.resources.and.institutions.of.a.country.or.region.to.implement.effective.adaptation.measures.
Climate
climate.in.a.narrow.sense.is.usually.defined.as.the.average.weather,.or.more.rigorously,.as.the.statistical.description.in.terms.of.the.mean.and.variability.of.relevant.quantities.over.a.period.of.time.ranging.from.months.to.thousands.or.millions.of.years..the.classical.period.for.averaging.these.variables.is.30.years,.as.defined.by.the.world.meteorological.organization..the.relevant.quantities.are.most.often.surface.variables.such.as.temperature,.precipitation.and.wind..climate.in.a.wider.sense.is.the.state,.including.a.statistical.description,.of.the.climate.system.
Climate change
climate.change.refers.to.a.change.in.the.state.of.the.climate.that.can.be.identified.(e.g.,.by.using.statistical.tests).by.changes.in.the.mean.and/or.the.variability.of.its.properties,.and.that.persists.for.an.extended.period,.typically.decades.or.longer..climate.change.may.be.due.to.natural.internal.processes.or.external.forcings,.or.to.persistent.anthropogenic.changes.in.the.composition.of.the.atmosphere.or.in.land.use..note.that.the.united.nations.Framework.convention.on.climate.change.(unFccc),.in.its.Article.1,.defines.climate.change.as:.a.change.of.climate.which.is.attributed.directly.or.indirectly.to.human.activity.that.alters.the.composition.of.the.global.atmosphere.and.which.is.in.addition.to.natural.climate.variability.observed.over.comparable.time.periods’..the.unFccc.thus.makes.a.distinction.between.climate.change.attributable.to.human.activities.altering.the.atmospheric.composition,.and.climate.variability.attributable.to.natural.causes.
Climate model
A.numerical.representation.of.the.climate.system.based.on.the.physical,.chemical.and.biological.properties.of.its.components,.their.interactions.and.feedback.processes,.and.accounting.for.all.or.some.of.its.known.properties..the.climate.system.can.be.represented.by.models.of.varying.complexity,.that.is,.for.any.one.component.or.combination.of.components.a.spectrum.or.hierarchy.of.models.can.be.identified,.differing.in.such.aspects.as.the.number.of.spatial.dimensions,.the.extent.to.which.physical,.chemical.or.biological.processes.are.explicitly.represented,.or.the.level.at.which.empirical.parameterisations.are.involved..coupled.Atmosphere-ocean.general.circulation.models.(Aogcms).provide.a.representation.of.the.climate.system.that.is.near.the.most.comprehensive.end.of.the.spectrum.currently.available..
134
there.is.an.evolution.towards.more.complex.models.with.interactive.chemistry.and.biology..climate.models.are.applied.as.a.research.tool.to.study.and.simulate.the.climate,.and.for.operational.purposes,.including.monthly,.seasonal.and.interannual.climate.predictions.
Climate projection
A.projection.of.the.response.of.the.climate.system.to.emissions.or.concentration.scenarios.of.greenhouse.gases.and.aerosols,.or.radiative.forcing.scenarios,.often.based.upon.simulations.by.climate.models..climate.projections.are.distinguished.from.climate.predictions.in.order.to.emphasize.that.climate.projections.depend.upon.the.emission/concentration/radiative.forcing.scenario.used,.which.are.based.on.assumptions.concerning,.for.example,.future.socioeconomic.and.technological.developments.that.may.or.may.not.be.realised.and.are.therefore.subject.to.substantial.uncertainty.
Climate scenario
A.plausible.and.often.simplified.representation.of.the.future.climate,.based.on.an.internally.consistent.set.of.climatological.relationships.that.has.been.constructed.for.explicit.use.in.investigating.the.potential.consequences.of.anthropogenic.climate.change,.often.serving.as.input.to.impact.models..climate.projections.often.serve.as.the.raw.material.for.constructing.climate.scenarios,.but.climate.scenarios.usually.require.additional.information.such.as.about.the.observed.current.climate..A.climate.change.scenario.is.the.difference.between.a.climate.scenario.and.the.current.climate.
Climate system
the.climate.system.is.the.highly.complex.system.consisting.of.five.major.components:.the.atmosphere,.the.hydrosphere,.the.cryosphere,.the.land.surface.and.the.biosphere,.and.the.interactions.between.them..the.climate.system.evolves.in.time.under.the.influence.of.its.own.internal.dynamics.and.because.of.external.forcings.such.as.volcanic.eruptions,.solar.variations.and.anthropogenic.forcings.such.as.the.changing.composition.of.the.atmosphere.and.land-use.change.
Climate variability
climate.variability.refers.to.variations.in.the.mean.state.and.other.statistics.(such.as.standard.deviations,.the.occurrence.of.extremes,.etc.).of.the.climate.on.all.spatial.and.temporal.scales.beyond.that.of.individual.weather.events..variability.may.be.due.to.natural.internal.processes.within.the.climate.system.(internal.variability),.or.to.variations.in.natural.or.anthropogenic.external.forcing.(external.variability).
Confidence
As.defined.by.the.iPcc,.the.degree.of.confidence.in.being.correct.is.described.as.follows:
very.high.confidence.. At.least.9.out.of.10.chance.of.being.correct
High.confidence.. About.8.out.of.10.chance
medium.confidence.. About.5.out.of.10.chance
low.confidence.. About.2.out.of.10.chance
very.low.confidence.. less.than.a.1.out.of.10.chance
135
detection and attribution
climate.varies.continually.on.all.time.scales. Detection of.climate.change is.the.process.of demonstrating.that.climate.has.changed.in some.defined.statistical.sense,.without providing.a.reason.for.that.change..Attribution of.causes.of.climate.change.is.the.process.of establishing.the.most.likely.causes.for.the detected.change.with.some.defined.level.of confidence.
downscaling
downscaling.is.a.method.that.derives.local-to.regional-scale.(10.to.100km).information.from.larger-scale.models.or.data.analyses..two.main.methods.are.distinguished:.dynamical.downscaling.and.empirical/statistical.downscaling..the.dynamical.method.uses.the.output.of.regional.climate.models,.global.models.with.variable.spatial.resolution.or.high-resolution.global.models..the.empirical/statistical.methods.develop.statistical.relationships.that.link.the.large-scale.atmospheric.variables.with.local/regional.climate.variables..in.all.cases,.the.quality.of.the.downscaled.product.depends.on.the.quality.of.the.driving.model.
emissions scenario
A.plausible.representation.of.the.future.development.of.emissions.of.substances.that.are.potentially.radiatively.active.(e.g.,.greenhouse.gases,.aerosols),.based.on.a.coherent.and.internally.consistent.set.of.assumptions.about.driving.forces.(such.as.demographic.and.socioeconomic.development,.technological.change).and.their.key.relationships..concentration.scenarios,.derived.from.emission.scenarios,.are.used.as.input.to.a.climate.model.to.compute.climate.projections..in.iPcc.(1992).a.set.of.emission.scenarios.was.presented.which.were.used.as.a.basis.for.the.climate.projections.in.iPcc.(1996)..these.emission.scenarios.are.referred.to.as.the.is92.scenarios..in.the.iPcc.special.report.on.emission.scenarios.(nakićenović.and.swart,.2000).new.emission.scenarios,.the.so-called.sres.scenarios,.were.published.
ensemble
A.group.of.parallel.and.model.simulations.used.for.climate.projections..variation.of.the.results.across.the.ensemble.members.gives.an.estimate.of.uncertainty..ensembles.made.with.the.same.model.but.different.initial.conditions.only.characterise.the.uncertainty.associated.with.internal.climate.variability,.whereas.multi-model.ensembles.including.simulations.by.several.models.also.include.the.impact.of.model.differences..Perturbed-parameter.ensembles,.in.which.model.parameters.are.varied.in.a.systematic.manner,.aim.to.produce.a.more.objective.estimate.of.modelling.uncertainty.that.is.possible.with.traditional.multi-model.ensembles.
exposure
in.this.context.of.this.report,.exposure.refers.to.bank.projects.and/or.regional.investments.being.subjected.to.negative.changes.in.annual.runoff.(from.present.day.values).in.the.year.2030.or.2050..the.climate.change.exposure.index.was.defined.as.follows.for.all.projects.except.flood.control.projects:
136
Exposure Index Description
Water systems (non flood control)
low. %.reduction.in.annual.runoff…..less.than.5%
medium. %.reduction.in.annual.runoff…..between.5.and.15%
High. %.reduction.in.annual.runoff…..more.than.15%
Flood control system
low. %.reduction.in.annual.runoff…..more.than.15%
middle. .%.reduction.in.annual.runoff…..between.5.and.15%
High.. .%.reduction.in.annual.runoff…..less.than.5%
flexibility
the.flexibility.of.a.system.refers.to.its.ability.to.adapt.to.a.wide.range.of.operating.conditions.through.relatively.modest.and.inexpensive.levels.of.redesign,.refitting.or.reoperation.(Hashimoto,.t..et.al.,.1982a).
general Circulation model
see.Climate model.
greenhouse effect
greenhouse.gases.effectively.absorb.thermal.infrared.radiation,.emitted.by.the.earth’s.surface,.by.the.atmosphere.itself.due.to.the.same.gases,.and.by.clouds..Atmospheric.radiation.is.emitted.to.all.sides,.including.downward.to.the.earth’s.surface..thus.greenhouse.gases.trap.heat.within.the.surface.troposphere.system..this.is.called.the.greenhouse.effect..thermal.infrared.radiation.in.the.troposphere.is.strongly.coupled.to.the.temperature.of.the.atmosphere.at.the.altitude.at.which.it.is.emitted..in.the.troposphere,.the.temperature.generally.decreases.with.height..effectively,.infrared.radiation.emitted.to.space.originates.from.an.altitude.with.a.temperature.of,.on.average,.–19°c,.in.balance.with.the.net.incoming.solar.radiation,.whereas.the.earth’s.surface.is.kept.at.a.much.higher.temperature.of,.on.average,.+14°c..An.increase.in.the.concentration.of.greenhouse.gases.leads.to.an.increased.infrared.opacity.of.the.atmosphere,.and.therefore.to.an.effective.radiation.into.space.from.a.higher.altitude.at.a.lower.temperature..this.causes.a.radiative.forcing.that.leads.to.an.enhancement.of.the.greenhouse.effect,.the.so-called.enhanced.greenhouse.effect.
greenhouse gas (gHg)
greenhouse.gases.are.those.gaseous.constituents.of.the.atmosphere,.both.natural.and.anthropogenic,.that.absorb.and.emit.radiation.at.specific.wavelengths.within.the.spectrum.of.thermal.infrared.radiation.emitted.by.the.earth’s.surface,.the.atmosphere.itself,.and.by.clouds..this.property.causes.the.greenhouse.effect..water.vapour.(H2o),.carbon.dioxide.(co2),.nitrous.oxide.(n2o),.methane.(cH4).and.ozone.(o3).are.the.primary.greenhouse.gases.in.the.earth’s.atmosphere..moreover,.there.are.a.number.of.entirely.human-made.greenhouse.gases.in.the.atmosphere,.such.as.the.halocarbons.and.other.chlorine.and.bromine.containing.substances,.dealt.with.under.the.montreal.Protocol..beside.co2,.n2o.and.cH4,.the.kyoto.Protocol.deals.with.the.greenhouse.gases.sulphur.hexafluoride.(sF6),.hydrofluorocarbons.(HFcs).and.perfluorocarbons.(PFcs).
137
Hydrological cycle
the.cycle.in.which.water.evaporates.from.the.oceans.and.the.land.surface,.is.carried.over.the.earth.in.atmospheric.circulation.as.water.vapour,.condensates.to.form.clouds,.precipitates.again.as.rain.or.snow,.is.intercepted.by.trees.and.vegetation,.provides.runoff.on.the.land.surface,.infiltrates.into.soils,.recharges.groundwater,.discharges.into.streams,.and.ultimately,.flows.out.into.the.oceans,.from.which.it.will.eventually.evaporate.again.(Ams,.2000)..the.various.systems.involved.in.the.hydrological.cycle.are.usually.referred.to.as.hydrological.systems.
(Climate change) impacts
the.effects.of.climate.change.on.natural.and.human.systems..depending.on.the.consideration.of.adaptation,.one.can.distinguish.between.potential.impacts.and.residual.impacts:
•.Potential impacts:.all.impacts.that.may.occur.given.a.projected.change.in.climate,.without.considering.adaptation.
•.Residual impacts:.the.impacts.of.climate.change.that.would.occur.after.adaptation.
likelihood
As.defined.by.the.iPcc,.the.likelihood.of.the.occurrence/outcome.is.described.below:
virtually.certain.. >99%.probability.of.occurrence
very.likely.. 90.to.99%.probability
likely.. 66.to.90%.probability
About.as.likely.as.not.. 33.to.66%.probability
unlikely.. 10.to.33%.probability
very.unlikely.. 1.to.10%.probability
exceptionally.unlikely.. <1%.probability
mitigation
technological.change.and.substitution.that.reduce.resource.inputs.and.emissions.per.unit.of.output..Although.several.social,.economic.and.technological.policies.would.produce.an.emission.reduction,.with.respect.to.climate.change,.mitigation.means.implementing.policies.to.reduce.greenhouse.gas.emissions.and.enhance.sinks.
no-regrets policy
A.policy.that.would.generate.net.social.and/or.economic.benefits.irrespective.of.whether.or.not.anthropogenic.climate.change.occurs.
Projection
A.potential.future.evolution.of.a.quantity.or.set.of.quantities,.often.computed.with.the.aid.of.a.model..Projections.are.distinguished.from.predictions.in.order.to.emphasize.that.projections.
138
involve.assumptions.concerning,.for.example,.future.socioeconomic.and.technological.developments.that.may.or.may.not.be.realised,.and.are.therefore.subject.to.substantial.uncertainty.
reliability
reliability.is.defined.as.the.likelihood.that.services.are.delivered.(no.failure).within.a.given.period,.expressed.as.a.probability..High.probabilities.indicate.high.reliability.(Hashimoto,.t..et.al.,.1982b).
resilience
A..the.ability.of.a.social.or.ecological.system.to.absorb.disturbances.while.retaining.the.same.basic.structure.and.ways.of.functioning,.the.capacity.for.self-organization,.and.the.capacity.to.adapt.to.stress.and.change.
b..resiliency.is.the.speed.at.which.the.system.recovers.from.a.failure,.on.average..shorter.recovery.periods.indicate.higher.resiliency.(Hashimoto,.t..et.al.,.1982b).
risk
the.potential.for.realization.of.unwanted,.adverse.consequences;.usually.based.on.the.expected.result.of.the.conditional.probability.of.the.occurrence.of.the.event.multiplied.by.the.consequence.of.the.event,.given.that.it.has.occurred..what.makes.a.situation.risky.rather.than.uncertain.is.the.availability.of.objective.estimates.of.the.probability.distribution..(usAce,.1992)
robustness
in.a.water.resources.system,.robustness.refers.to.the.extent.to.which.a.system.design.is.able.to.deliver.optimal.or.near-optimal.levels.of.service.over.a.range.of.demand.(input).and.supply.(resource).conditions.(Hashimoto,.t..et.al.,.1982a).
scenario
A.plausible.and.often.simplified.description.of.how.the.future.may.develop,.based.on.a.coherent.and.internally.consistent.set.of.assumptions.about.driving.forces.and.key.relationships..scenarios.may.be.derived.from.projections,.but.are.often.based.on.additional.information.from.other.sources,.sometimes.combined.with.a.narrative.storyline.
sensitivity
sensitivity.is.the.degree.to.which.a.system.is.affected,.either.adversely.or.beneficially,.by
climate.variability.or.climate.change..the.effect.may.be.direct.(e.g.,.a.change.in.crop.yield.in.response.to.a.change.in.the.mean,.range,.or.variability.of.temperature).or.indirect.(e.g.,.damages.caused.by.an.increase.in.the.frequency.of.coastal.flooding.due.to.sea.level.rise).
stationarity
stationarity.assumes.that.natural.systems.fluctuate.within.an.unchanging.envelope.of.variability..stationarity.is.a.foundational.concept.that.permeates.training.and.practice.in.water-resource.engineering..it.implies.that.any.variable.(e.g.,.annual.streamflow.or.annual.flood.peak).has.a.
139
time-invariant.(or.1-year–periodic).probability.density.function.(pdf),.whose.properties.can.be.estimated.from.the.instrument.record..under.stationarity,.pdf.estimation.errors.are.acknowledged,.but.have.been.assumed.to.be.reducible.by.additional.observations,.more.efficient.estimators,.or.regional.or.paleohydrologic.data..the.pdfs,.in.turn,.are.used.to.evaluate.and.manage.risks.to.water.supplies,.waterworks,.and.floodplains.(milly.et.al.,.2008).
Threshold
the.level.of.magnitude.of.a.system.process.at.which.sudden.or.rapid.change.occurs..A.point.or.level.at.which.new.properties.emerge.in.an.ecological,.economic.or.other.system,.invalidating.predictions.based.on.mathematical.relationships.that.apply.at.lower.levels.
uncertainty
A..An.expression.of.the.degree.to.which.a.value.(e.g.,.the.future.state.of.the.climate system).is.unknown..uncertainty.can.result.from.lack.of.information.or.from.disagreement.about.what.is.known.or.even.knowable..it.may.have.many.types.of.sources,.from.quantifiable.errors.in.the.data.to.ambiguously.defined.concepts.or.terminology,.or.uncertain.projections of.human.behaviour..uncertainty.can.therefore.be.represented.by.quantitative.measures,.for.example,.a.range.of.values.calculated.by.various.models,.or.by.qualitative.statements,.for.example,.reflecting.the.judgment.of.a.team.of.experts.
b..uncertain.situations.are.those.in.which.the.probability.of.potential.outcomes.and.their.results.cannot.be.described.by.objectively.known.probability.distributions,.or.the.outcomes.themselves,.or.the.results.of.those.outcomes.are.indeterminate.(usAce,.1992)
united nations framework Convention on Climate Change (unfCCC)
the.convention.was.adopted.on.9.may.1992.in.new.york.and.signed.at.the.1992.earth.summit.in.rio.de.janeiro.by.more.than.150.countries.and.the.european.community..its.ultimate.objective.is.the.“stabilisation.of.greenhouse.gas.concentrations.in.the.atmosphere.at.a.level.that.would.prevent.dangerous.anthropogenic.interference.with.the.climate.system”..it.contains.commitments.for.all.Parties..under.the.convention,.Parties.included.in.Annex.i.(all.oecd.member.countries.in.the.year.1990.and.countries.with.economies.in.transition).aim.to.return.greenhouse.gas.emissions.not.controlled.by.the.montreal.Protocol.to.1990.levels.by.the.year.2000..the.convention.entered.in.force.in.march.1994.
vulnerability
A..vulnerability.is.the.degree.to.which.a.system.is.susceptible.to,.and.unable.to.cope.with,.adverse.effects.of.climate.change,.including.climate.variability.and.extremes..vulnerability.is.a.function.of.the.character,.magnitude,.and.rate.of.climate.change.and.variation.to.which.a.system.is.exposed,.its.sensitivity,.and.its.adaptive.capacity.
b..vulnerability.refers.to.the.severity.of.the.likely.or.expected.consequences.of.failure.(Hashimoto,.t..et.al.,.1982b).
ReferencesAms,.2000:.Ams.glossary.of.meteorology,.2nd.edition..American.meteorological.society,.boston,.
mA..http://amsglossary.allenpress.com/glossary/browse..
140
Hashimoto,.t.,.d.P..loucks,.and.j.r..stedinger..1982a..robustness.of.water.resources.systems..Water Resources Research.18(1):21–26.
Hashimoto,.t.,.j.r..stedinger,.and.d.P..loucks..1982b..reliability,.resiliency.and.vulnerability.criteria.for.water.resource.system.performance.evaluation..Water Resources Research.18(1):14–20.
iPcc,.1992..climate.change.1992:.the.supplementary.report.to.the.iPcc.scientific.Assessment.[Houghton,.j.t.,.b.A..callander,.and.s.k..varney.(eds.)]..cambridge.university.Press,.cambridge,.united.kingdom.and.new.york,.ny,.usA
iPcc..1996..climate.change.1995:.the.science.of.climate.change,.contribution.of.working.group.i.to.the.second.Assessment.report.of.the.intergovernmental.Panel.on.climate.change..j..t..Houghton,.l.g..meira.Filho,.b.A..callander,.n..Harris,.A..kattenberg,.and.k..maskell..(eds.)..cambridge,.england:.cambridge.university.Press.
iPcc,.2008,.technical.Paper.on.climate.change.and.water,.iPcc.secretariat,.geneva,.switzerland.
milly.et.al..2008..stationarity.is.dead:.wither.water.management?.Science.vol.319.nakićenović,.n..and.r..swart.(eds.),.2000:.Special Report on Emissions Scenarios..cambridge.
university.Press,.599.pp.usAce.(us.Army.corps.of.engineers)..1992..guidelines.for.risk.and.uncertainty.Analysis.
in.water.resources.Planning,.vol.1.–.Principles..iwr.report.92-r-1..institute.for.water.resources..Fort.belvoir,.usA.
